bamboostreet
100+ Head-Fier
I always thought it was crazy to pay $5 a pair for eartips for a tiny piece of silicone. I use BGVP A07 which is a more affordable copy of KBEAR A07. If you want a guide, a repertoire, it's the Tweaking tips from Audio Reviews
https://www.audioreviews.org/guide-to-iem-silicone-eartips/
https://www.audioreviews.org/guide-to-iem-silicone-eartips/