Trackers
The most useful trackers. Most of them are DOS applications.
Subz3ro's ADLIB TRACK3R 2 G3 ver.2.3.38 (Protected Mode) with MACROS and 4OP mode

THE MOST ADVANCED OPL3 TRACKER EVER! Supports 18-channels, percussion mode, 4op mode, 2nd effect column, 8-waveforms, sound macrodefinitions (including arpeggiator and vibrato), stereo, advanced editing, textmode-emulator and even more module/instruments formats then ever. A lot of commands and really BIG instrument/module collection. Player source (Pascal) included.
This is the most capable OPL3 tracker you can found and it sounds even better than EdLib:)
1190KB
EdLib OPL3 patch EdLib OPL3

Hack to famous EdLib! Enables OPL3 features like: 8 waveforms, stereo and MUCH FASTER replay routine (OPL3 is simply faster :). Needs original Edlib composer. Great hack! TRY IT!
24KB
Subz3ro's ADLIB TRACK3R 2 ver.2r27

Older version of Subz3ro's AdLib tracker. A lot of commands and really BIG instrument/module collection. Player source (Pascal) included. TRY IT! I've decided to not drop it because it supports OPL2 - the newest version supports OPL3 only.
407KB
TFM Music Maker 1.3

Win32 tracker NOT for AdLib. With that masterpiece you can make a music for SEGA Mega Drive (YM2612 (OPN2) chip) and Turbo Sound FM (2xYM2203 (OPN) chip) soundcard for ZX Spectrum.
935KB
BeRo Mini Tracker

Win32 tracker. This software use OPL2/OPL3 emulation instead of original hardware. It loads very popular HSC file format.
211KB
Composer 667

Very old and special OPL2 tracker by Tran/Renaissance. It can use stereo Dual-OPL2 mode on Sound Blaster Pro 1.0! I'm really curious if it's similar to my Holy Grail - the CDFM Tracker from Renaissance...
19KB
Boom Tracker 4.0+

Tracker with interface similar to the Scream Tracker. Looks very nice.
187KB
Amusic 1.12

Nice VGA interface with mouse support. Arpeggios 2 times slower (but it sounds good :)! In this version you can load Protracker modules.
88KB
EdLib 1.05a

Best sound quality, because of instrument macros!
Interface a'la C64 editors (track, not pattern oriented).
129KB
Surprise! Adlib Tracker 2.0 Surprise! AdLib Tracker 2.0

Tracker with instrument arpeggiators.
190KB
Reality AdLibTracker 1.1

Nice, small tracker. Can read AdLib type S3M modules.
110KB
FM-Kingtracker 1.06

Supports OPL3 (2/4-operarator modes, 18 channels, stereo, 8 waveforms)! ST3-like interface.
113KB
Scream Tracker 3.21 Scream Tracker 3.21

Famous S3M Tracker with AdLib support.
179KB
Arkham Master Tracker 2.4 Arkham Master Tracker 2.4

Rather strange AdLib tracker...
144KB
Digital-FM 1.1 Digital-FM 1.1 (DFM)

Tracker with instrument editor and bank of instruments.
97KB
Faust Music Creator Faust Music Creator

Small AdLib tracker with 8 (why?) sound channels. Player source  (ASM) included.
31KB
Game Music System 1.0 Game Music System1.0

Interesting tracker that supports AdLib/SoundBlaster (OPL2), Sound Blaster Pro I (2xOPL2- stereo), Sound Blaster Pro II (OPL3 - stereo). Can load RAD modules. Player source (C) included.
118KB
HSC Tracker 1.5 HSC-Tracker 1.5

The one and only HSC tracker! Old but it starts AdLib scene (...in my opinion...). Look at oldsk00l!
A LOT of example modules!
148KB
FM Tracker 2.0 FM Tracker 2.0

Tracker that supports HSC modules. Loads DFM tunes too.
117KB
Note 1.0 beta2 Note 1.0 beta2

Somebody can tell me how it works?! Documentation is Korean?? Looks like a MIDI sequencer with ST3-like interface...Supports OPL3 (4-operator synthesis can be enabled!) in percussion mode - 20 channels (15 tone + 5 percussion channels). Supports SOP files.
88KB
XMS-Tracker 1.0b XMS-Tracker 1.0b

Looks like unfinished, cracked Amusic! Hmmm...
59KB
FM-Tracker 1.45

Tracker that supports melody and PERCUSSION mode! A LOT of commands.
78KB
DeFy Adlib Tracker 1.0

OPL3 tracker - uses stereo but no new waveforms. Nice interface.
112KB
Mlat Adlib Tracker 1.3 Mlat ADlib tracker 1.3

Simple AdLib tracker written in PowerBASIC.
93KB
Mlat Adlib Tracker 1.3 Frankus Tracker

Simple AdLib tracker written in QBASIC.
64KB
The FM Tracker 1.1 The FM Tracker 1.1b

Another AdLib tracker written in BASIC :) 
114KB
Mlat Adlib Tracker 1.3 Adlib Tracker 1.0

Yet another AdLib tracker :) 
75KB
Mlat Adlib Tracker 1.3 Beni Tracker v1.8

Simple AdLib tracker written in QBASIC.
101KB