The best referral codes for ByBit in 2023 are `LIMIT` for a deposit of $3,000 & trade of $6k to earn $100, `PROMO` for a deposit of $20k & trade of $200k to earn $800, `FREEBITS` for a deposit of $125k & trade of $50m to earn $8,800, and `PROMO` for a deposit of $250k & trade of $150m to earn $30,000.