Binance were doing a promotion some time ago (it might still be active and probably is) for trading without fees.
Aside from that I don't think there's options without exchanges the recoup fees based on spreads.
Binance is the best option
These are the trading zero fee pairs:
https://www.binance.com/en/support/announcement/10435147c55d4a40b64fcbf43cb46329BTC/AUD, BTC/BIDR, BTC/BRL, BTC/BUSD, BTC/EUR, BTC/GBP, BTC/RUB, BTC/TRY, BTC/TUSD, BTC/UAH, BTC/USDC, BTC/USDP and BTC/USDT.
Those are basically fiat and stable coins.