Science: BC Arbitrary Maths, GMP,

Compression: BZip2, LZF, rar, Zip, zlib

Date/time: Calendar

Interop: COM/.Net, Java

Protocols: Curl, IMAP, Direct-IO, FTP, IRCg, LDAP, mailparse, NIS, OpenSSL, SNMP

Databases: DBM, dBase, db++, dbx, FrontBase, filePro, Hyperwave, Interbase, Informix, Ingress II, MaxDB, mSQL, MSSQL, MySQL, Oracle, Ovrimos, PDO, PostGreSQL, Sesam, SQLite, Sybase, ODBC

XML: DOM, SimpleXML, SOAP, WDDX, XML-RPC, XSLT

Graphics: ClibPDF, GD, Exif, mimetype, Ming, PDFLib/FDF

Internationalisation: FriBiDi, Gettext, iconv, mbstring, Pspell, recode

Encryption: MCrypt, MHash

System like functions: Process Control, POSIX, Semaphore, Shared Memory, socket

Others: mnogosearch, ncurses, Regular Expressions, POSIX, Printer, SPL, xdiff