Ehm,

- Mining Monero

- Trading goods or services for XMR

- Providing freelance work on platforms that pay in Monero

- Participating in Monero bounty programs or development efforts

- Arbitrage trading between exchanges (cex vs dex)

- Staking in Monero lending platforms (very risky)

- Running a Monero node and offering services (like VPNs) for XMR payments

- Accepting Monero for business transactions (e-commerce, etc.)

Probably more ...