Hello everyone!
I have created the following list with all the 
keycap (keysets, not artisans) 
manufacturers I know:
MANUFACTURER  |  MATERIAL(S)  |  MAIN PROD. METHOD(S)  |  MAIN PROFILE(S)  |  PRICING ($-$$$$)  |  QUALITY1        *NOTES1 Basic < Not bad < Good < Very good < Top tier
2 Yellow color means "Lack of information / Possible known mistake"More
AIFEI / GLIGING / SUMGSN / VENIT KEYS / YONG-QIU    ABS / PBT    Doubleshot / Dye-sub & Reverse dye-sub    Cherry, SA    $    Basic        *Clones
AKKO-EPOMAKER    PBT / PC    Doubleshot / Dye-sub & Reverse dye-sub / UV print    ASA, Cherry, OEM, OSA    $$    Not bad
ALL.CAPS    PBT    Dye-sub    Cherry    $$$    Good
ANGRY MIAO    PBT / PC    Dye-sub / Laser etched-engraving    Unique-Unknown    $$$    Good
BSP EUROPE (BSP)    PBT    Dye-sub    Cherry    $$$    Good
CANNONCAPS    PBT    Dye-sub & Reverse dye-sub    Cherry    $$$    Very good        *Property of CANNONKEYS
OG CHERRY    ABS / PBT / POM    Doubleshot / Dye-sub / Laser etched-engraving / UV print   Cherry    $$$$    Top tier        *Only found in vintage keyboards sold in second-hand market
CONTRAKEY    PBT    Dye-sub    Cherry    $$    Good
CREATEKEEBS a.k.a. ESC.HIT    ABS-PBT    Dye-sub & Reverse dye-sub    Cherry    $$-$$$    Good        *Cooperating with ALOHAKB
DEADLINE STUDIO (DEADLINE)    PC    Laser etched-engraving    Cherry    $$$    Good
DOMIKEY (DMK)    ABS / PBT   Doubleshot & Tripleshot / Dye-sub   Cherry, SA    $$$$    Top tier
DROP (Artifact Bloom Series, DCX & MT3)    ABS / PBT    Doubleshot / Dye-sub & Reverse dye-sub    Cherry, MT3    $$-$$$    Very good
DUCKY    PBT    Doubleshot    OEM    $$    Not bad
ENJOY PBT (ePBT)    ABS / PBT    Doubleshot / Dye-sub & Reverse dye-sub    Cherry    $$$-$$$$    Very good
GEEKARK    PBT    Dye-sub & Reverse dye-sub    Cherry    $$$    Very good
GLORIOUS (GPBT)    PBT    Dye-sub & Reverse dye-sub    Cherry    $$    Good
GLOVE    PBT    Pad print & UV coat    WDA    $$$$    Good
GMK-UNIQEY    ABS    Doubleshot / UV print    Cherry    $$$$    Top tier        *Owner of the original CHERRY molds
HAMMERWORKS CRP    PBT    Dye-sub & Reverse dye-sub    Cherry    $$$    Top tier
HK GAMING    PBT    Dye-sub    Cherry    $    Basic
IDOBAO    PBT    Dye-sub & Reverse dye-sub    Cherry, MA, OEM    $-$$    Not bad
INFINIKEY (IFK)    PBT    Dye-sub & Reverse dye-sub    Cherry    $$$    Very good        *Property of THE KEY COMPANY
IV WORKS    PBT    Dye-sub & Reverse dye-sub    Cherry    $$$    Very good
JKDK    PBT    Dye-sub & Reverse dye-sub    Cherry    $$    Good        *AliExpress legit/original manufacturer?
JT KEYCAPS (JTK)    ABS    Doubleshot & Tripleshot    Cherry    $$$$    Top tier
KBDFans    PBT    Dye-sub & Reverse dye-sub / Laser etched-engraving    Cherry, DSA    $-$$    Good
KEEBMONKEY    PBT    Dye-sub & Reverse dye-sub    Cherry    $$-$$$    Good
KEYBEE (KBM)    PBT    Dye-sub & Reverse dye-sub    Cherry    $$$    Very good
KEYCHRON    PBT    Doubleshot / Dye-sub & Reverse dye-sub    Cherry, OEM, OSA    $-$$    Not bad
KEYKOBO (KK)    ABS    Doubleshot    Cherry    $$$    Very good
KEYREATIVE    PBT    Doubleshot / Dye-sub & Reverse dye-sub    KAM, KAT    $$$    Very good
KINETIC LABS    PBT    Doubleshot / Dye-sub    Cherry    $$$    Good
KONO DESIGNER SERIES (KDS)    PBT    Dye-sub & Reverse dye-sub    Cherry    $$$    Very good
KPREPUBLIC    PBT    Doubleshot / Dye-sub    Cherry, CSA    $-$$    Good
LELELAB    ABS    Unknown    Unknown    $$    Good
LEOPOLD    PBT    Doubleshot    OEM    $$    Not bad
MAX KEYBOARDS (MX)    ABS / PC    Laser etched-engraving / UV print    OEM    $$    Basic        *Can produce individual custom keysets
MAXKEY    PBT    Doubleshot / Dye-sub & Reverse dye-sub    SA    $$-$$$    Good
MELGEEK (MG)    ABS / PBT    Doubleshot / Dye-sub    MDA, MG    $$$    Very good
MILKYWAY KEYS (MW)    PBT    Doubleshot / Dye-sub & Reverse dye-sub    Cherry    $$$$    Top tier
MODE DESIGNS (MODE)    ABS    Doubleshot    Cherry    $$$    Good
MONOKEI    PBT    Doubleshot    Cherry    $$$    Very good
MONSTARGEAR    ABS / PBT    Doubleshot / Dye-sub    Cherry, MG, OEM    $-$$$    Good
"MVKB (MV)"    PBT    Dye-sub & Reverse dye-sub    Cherry    $$$    Very good        *According to designer, Max Voltar, MV means "Sets produced by a variety of factories that have been approved by him"
NicePBT    PBT    Dye-sub & Reverse dye-sub / Laser etched-engraving    Cherry, DSA    $$$    Very good        *Property of CANNONKEYS
NOVELKEYS (NK)    PBT    Dye-sub & Reverse dye-sub    Cherry, DSA    $$$    Very good
NUPHY    PC+ABS / PBT    Doubleshot    Cherry-like, Low profile    $    Good
OMNITYPE (OTC)    PBT    Dye-sub & Reverse dye-sub    Cherry    $$$    Good
OSUMEKEYS (OSUME)    PBT    Dye-sub & Reverse dye-sub    Cherry    $$$    Good
PBTFans    ABS / PBT    Doubleshot & Tripleshot / UV print    Cherry    $$$    Top tier        *Property of KBDFans
PG    PBT    Dye-sub & Reverse dye-sub    NP/PG    $$    Not bad
QUALITY PBT (qPBT)    PBT    Dye-sub & Reverse dye-sub    Cherry    $$    Not bad
RAMA WORKS (RW)    PC    Doubleshot    Unique    $$$$    Very good
SHENPO    PBT    Dye-sub    Cherry    $    Good
SHURIKEY    ABS    Doubleshot    Cherry    $$    Good
SIGNATURE PLASTICS (SP)-PIMP MY KEYBOARD    ABS / PBT    Doubleshot / Dye-sub & Reverse dye-sub    DCS, DSA, DSS, SA    $$$$    Top tier        *Include Comptec keycaps
SwagKeys (SW)    PBT    Doubleshot    Cherry    $$$    Good
TAI-HAO    ABS / PBT    Doubleshot    Bobo (unique), OEM    $$    Not bad
TEACAPS (TeaPBT)    PBT    Dye-sub & Reverse dye-sub    Cherry    $$-$$$    Good
TECSEE    PBT    Doubleshot    Cherry    $$    Not bad
TEX ELECTRONICS (TEX)    ABS    Laser etched-engraving    TEX ADA    $    Not bad
TOMATOCAPS (TMT)    PBT    Dye-sub & Reverse dye-sub    Cherry    $$$    Good        *Partnering with zFRONTIER
TOMO CAPS (TOMO)    PBT    Dye-sub & Reverse dye-sub    Cherry    $$$    Very good
TRAITORS    PBT    Dye-sub & Reverse dye-sub    Cherry    $$    Not bad
VARMILO    PBT    Dye-sub & Reverse dye-sub    OEM    $$    Not bad
VORTEX KEYBOARD (VTK)    PBT / PBT-POM    Doubleshot / Dye-sub    OEM    $    Not bad        *Also known as VORTEXGEAR or simply VORTEX
WASD    ABS    UV coat    OEM    $$    Basic        *Can produce individual custom keysets
WINMX    PBT    Doubleshot / Dye-sub & Reverse dye-sub    Cherry, OSA, SA    $-$$    Good
WORK LOUDER (wrk.)    ABS / PC    Laser etched-engraving    Low profile Kaihl choc    $$$    Good
WuquePBT (WS)    PBT    Doubleshot / Dye-sub & Reverse dye-sub    Cherry    $$$    Good
YMDK    ABS / PBT    Dye-sub & Reverse dye-sub / Laser etched-engraving    Cherry, DSA, OEM, XDA    $    Basic
XIAMI (XMI)-21KB    PBT    Dye-sub    Cherry    $$$    Very good
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Last update (03 January 2023): OG CHERRY, DMK and ePBT modified, SW added.
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Data are based on public info, since obviously I have not tested a set from all of them. 
There can be mistakes; so please, feel free to give me feedback to amend them.
It is an 
open and 
editable list. My idea is that people can fulfill gaps, giving their "most objective" opinion, in such a way that The Community can maintain the list updated.
PD: It is not my aim to create a "fandom war" among people. The main goal of this list is giving a quick consulting guide to designers, customers and enthusiasts in general who look for basic information about keycap manufacturers.