Project Jedi ^[1] has an enormous number of components, and they are still actively developed. Here's a link to the sourceforge download site. ^[2]

Virtual Treeview, probably THE BEST visual control I have used. It may appear to be dead but that is only because it is so stable/mature!

http://www.soft-gems.net/index.php?option=com_content&task=view&id=12&Itemid=33 ^[1]

Virtual Shell Tools, Windows shell components based on Virtual Treeview.

http://www.mustangpeak.net/

SpTBXLib, very nice skin components.

http://www.silverpointdevelopment.com/

I just started the HTMLViewer project on sourceforge ^[1], to support the future development of the HTML viewer components, originally sold by PBear ^[2] (which are now put in the public domain by it's author, David Baldwin). We plan on porting it to Delphi 2009 (and possibly FPC). Cheers!

DUnit (http://dunit.sourceforge.net/) is THE unit testing framework for Delphi. It is updated for Delphi 2009 too, in the latest branch.

FreePascal and Lazarus. the tools if you need to support 64 bits or a different platform.

[edit] Hmm, I'm getting negative marks for suggesting the most important pieces of OSS for the Delphi market. That is shortsighted. The past few years it has been difficult getting management support for developing in Delphi, especially new products. Having a fall-back strategy is crucial.

I've been waiting for 64-bit support in Delphi since 2001.

CnPack ^[1] multilang InterNet Graphics NonVisual, Visual ...

For those interested : Sebastian Zierer keeps a repository of components ported to Delphi 2009 ^[1]. (Most are open-source, but not all.)

Graphics32 - FAST bitmap manipulation

Graphics32 is a graphics library for Delphi and Kylix/CLX. Optimized for 32-bit pixel formats, it provides fast operations with pixels and graphic primitives. In most cases Graphics32 considerably outperforms the standard TBitmap/TCanvas methods.

http://sourceforge.net/projects/graphics32

ZipMaster http://www.delphizip.org

Delphi Twain http://delphitwain.sourceforge.net

Synapse (network communication Library) http://synapse.ararat.cz

AsyncPro (former Turbo Power) is still running fine and keept updated. Perfect for all serial communication (RS232)

From what I can tell Indy 10 has been ported, but Indy 9 is not completely ported. I did a diff on Indy 9 and there were only a few changes between Delphi 2007 and 2009.

ICS - Internet Component Suite ^[1]

A fully featured set of internet tools: HTTP, NNTP, SMTP etc.

Synapse ^[1], a blocking TCP/IP library has been recently updated to support Delphi 2009. Extremely useful when you are performing TCP/IP communication in a background thread.

tiOPF Free, Open Source Object Persistence Framework forFree Pascal & Delphi http://tiopf.sourceforge.net/

The learning curve can be a little steep but there is an active community and the framework is very well suited to CRUD applications. Data can be persisted to xml or most of the major DBs. Except for very complicated object relationships, you do not need to write any SQL.

Most of my major projects include user scripting via RemObjects' PascalScript, available from http://www.remobjects.com/ps.aspx

It can be easily (relatively) integrated with your code. The main downside is that formal documentation is poor, although support forum is quite active.

Code has been recently updated to support unicode/D2009 although not yet sure how well this has been implemented. Although not perfect, it allows my users to customise features in ways that are difficult to achieve any other way. Bravo.

Zeoslib ^[1] provides native database access through BDE-alike components and also through ZDBC, a JDBC API ported to Delphi ^[2]. It supports several databases, such as postgresql, mysql, sqlite, firebird and others.

There's a web browser extension component called TWebBrowser available from www.bsalsa.com ^[1] that is pretty good. Their web site just suffered a bit fo a setback and the message base is getting repaired. The available version worked well with versions up to 2007. Someone is working on a Delphi 2009 version right now.

Delphi VNC ^[1]

Delphi components to support VNC application development.

TDBF - dBASE III+, dBase IV and dBase 2k

A freeware native data access component for Borland Delphi, C++Builder and Kylix, and for FreePascal. It allows you to create very compact database programs that don't need any special installer programs. In fact the code to access your database is compiled in your project executable file. It takes only a few kilobytes in your executable and doesn't need any other external files to run. File format 100% compatible with dBASE III+, dBase IV and dBase 2k.

I use it to read/write a very old database and it works like charm.

http://tdbf.sourceforge.net/

DSPack (a DirectShow library for media playback) has been ported. Info is available at http://www.progdigy.com

Scalabium ^[1] has a suite of free components. Their TSMDBGrid ^[2] is one of the best open source non obtrusive grids.

ti Object Persistence Framework

http://tiopf.sourceforge.net/

tiOPF is an Open Source framework for Delphi & Free Pascal that simplifies the mapping of an object oriented business model into a relational database.

OmniXML ^[1] - XML parser which can also be used to serialize / deserialize Delphi objects using RTTI.

SuperObject ^[2] - JSON library, JSON to XML parser, Validator

Mutis ^[1] is a Delphi port of the Lucene Search Engine. Provide a flexible API for index, catalog and search text-based information with great performance. Excelent for implement custom search engines, researching, text retrieval, data mining and more.

Spring4D – Delphi code library:
https://bitbucket.org/sglienke/spring4d/

TurboPower LockBox 3 is a FOSS delphi cryptographic library under active maintenance.

http://lockbox.seanbdurkin.id.au/ ; and http://sourceforge.net/projects/tplockbox/

We provide a lot of Open Source content for Delphi 6 up to XE:

• Client/Server ORM based on SQLite
• PDF writting library, supporting a TCanvas and Unicode
• GDI+ rendering from a normal TCanvas
• low level RTTI access
• SynBigTable which is a fast NoSQL local database engine
• Task Dialog unit working even before Vista/Seven
• fast (asm) cryptographic units
• a full source code versioning and documentation tool named SynProject
• and a lot of other stuff (http.sys fast Web server, Windows service handling, VCL light replacement...)

Our site is very active: http://synopse.info

Max Components has some nice Excel and export components that are free, plus others:

http://www.maxcomponents.net/index.php?id=1&page=1 ^[1]

Most are named already.

I also borrow a lot of (modified LGPL so safe) code from Lazarus/FPC for my delphi work, but I also use their image loaders as the basis for my own image format (to load png's, bmp's etc)

Also

For math stuff:

• http://www.efg2.com/Lab/Library/Delphi/MathFunctions/Engineering.htm examples
  • TPMath (cheap least squares linefit, originally for TP) Jedi Math's is/was too buggy.
  • Several expression parsers like Symbolic, ParseExpr.
• Comport for serial use. http://sourceforge.net/projects/comport/
• Freereport on sf (and, modified, as Lazreport in Lazarus) http://sourceforge.net/projects/freereport/ (and http://sourceforge.net/projects/lazreport/ )
• DCPCrypt(2) encryption http://www.cityinthesky.co.uk/cryptography.html

The JEDI API Library & Security Code Library ^[1]: The JWA library aims to provide a conversion from C to Delphi of as many headers as possible from the PSDK etc. The JWSCL (security library) is an advanced object-oriented framework for programming with the Windows security features (ACL, Tokens, etc.)

The team members (I'm one of them ;-) also keep a blog ^[2].

Report Manager ^[1] is a complete reporting solution avilable under the Mozilla Public License.

It has a designer, a (optional) server and can be compiled inside your .exe by Delphi.

The Delphi Cryptography Page DCP cryptographic components Written by David Barton (davebarton@bigfoot.com) http://www.scramdisk.clara.net/ very comprehensive, free to export, symmetric key cryptographic components

Open XML ^[1] is a collection of XML and Unicode tools and components.

InstantObjects Persistence Framework

InstantObjects ^[1]

InstantObjects is an Open Source Object Persistence Framework with integrated IDE modeling tools and support for many databases. The project was originally a commercial product of Seleqt.

The web site is out of date, but there is work happening on the developers forums. The framework now compiles are runs under on Delphi 2010 and 2009 with more enhancements on the way. Please check the SVN repository trunk for the latest code.

http://otl.17slon.com/ - OmniThreadLibrary seems to be very ambitious. Mitov's OpenWire is strong in using visual editor it provides. And is probably next to perfect for data streams. However sometimes visual editor is not so needed, and more generic less specialized library is wished for.

http://progdigy.com Unified Interbase - very lightweight and fast Data Access controls for Firebird and Interbase SQL servers. It is not so GUI-rich as FIBC+, and stable version was quite ago, but SVN versios work nice. It's design is a bit different from TTable/TQuery patterns and it is generally more SQLish and less ISAMic (for example, no TUpdateSQL-like helper). And need a bit of $IfDef configuring (it can be reduced to support only subset of database featurees/versions). So, maybe not for newcomer. But it is very slim OTOH.

Mitov Software ^[1] has some great free Delphi and CPP Builder components and experts. My favorites are:

• Image Debugger Visualizer
• Great threading components with ability to group threads and control the group of threads as a whole. Each thread is a visual component with OnStart and OnTerminate events (and of course, OnExecute). That makes code organization neater.