Fast loaders were written to speed up the actual loading time from tape using the ordinary Kernal ROM Routines. Also the actual quality of tapes was getting better and better, which made it possible to store data in a more and accurate way. Meaning it was possible to pack the "pulses" in other ways than how the ROM Loader did it.
The most commonly used loaders that has been identified and documented are the following
Accolade/EA Ace of Aces Loader Action Replay Alien Syndrome Alternative Software Alternative Software (DK) T1 Alternative Software (DK) T2 Alternative World Games American Action Anirog Anirog + Freeload Ash+Dave Atlantis Loader Audiogenic Loader Biturbo Bleepload Burner Burner (Mastertronic variant) CHR T1 CHR T1 + CHR T3 CHR T2 CHR T3 Chuckie Egg Loader Cult Loader Cyberload Cyberload+Creatures Enigma Loader Fast Evil FF Tape Firebird T1 Firebird T2 Flashload Freeload & Rainbow Islands Freeload (or clone) Freeload + Anirog Freeload Slowload Go For The Gold Graftgold Gremlin F1 Gremlin F2 Gremlin's Elder Tape Hi-Tec Loader Hit-load IK Tape Loader Jet-Load Microload Mikro-Gen v2 Novaload Ocean Loader (New) Ocean-Imagine F1 Ocean-Imagine F2 Ocean-Imagine F3 ODEload Palace Loader Pavloda Power Load Rack-it Rainbow Arts F1 Rainbow Arts F2 Rasterload ROM Loader SEUCK Loader Snakeload Super Pavloda T1 Super Pavloda T2 Supertape TDI Loader Tengen-Domark Loader Tequila Sunrise Trilogic Trilogic + CHR T1 Turbo Load Turbotape 250 (+clones) Turrican Loader U.S. Gold Loader U.S. Gold Loader + Cyberload Virgin Loader Visiload Wildload.