Very good question, but as you say it depends a lot on the coin/token that we want to buy or sell. Personally, I would start the list as follows:
Binance: 0.1% (tier 0).
Gate.io: Varies from 0.25% to 0.4%.
FTX: Varies from 0.02% to 0.07%.
Logically everything depends on the amounts and our KYC level, but the most important thing is the currency/token.