You have to routes
1 - Invest in offline business : Cafe, restaurant, real estate, SEO and SEM Agency .. and the list goes on and on
2 - Upgrade to higher invest, higher return projects in ur current online business : For example you said you have a good background in SEO, if you are making money out of it, then you know all about keyword research, landing pages, conversion ...etc
Then the logical updrade is ppc, exchange your time and effort with money.
Another example, if you are into affiliate marketing and already making money of it, then you know how to get interested traffic, and how to sell products to them. Then the next logical upgrades is dropshipping and selling your own products
and the list goes on ....