Glorious Gaming - What Are Mechanical Keyboard Orings?
Cherry Mx Rubber O-rings 120pcs Switch Dampeners Dark Black Clear Red Blue Cherry Mx Keyboard Dampers Keycap O Ring Replace Part - Keyboards - AliExpress
Parker Hannifin 2-008N674-70 O-Ring at SkyGeek.com
Amazon.com: ThreeBulls 120Pcs Clear Rubber O-Ring Switch Dampeners Keycap White for Cherry MX Key Switch Keyboards Dampers : Electronics
Glorious sell 40A/70A O-Rings at both 1.5 and 2.5mm for $10. Thought I'd mention this as usually people only talk about WASD. (link in comments) : r/MechanicalKeyboards