A mix of consulting, products and bitcoin. Happened to just be in a right place at the right time, and took (mostly) the right risks. Basically I went from zero net worth to 2-3 million liquid, within about 7 years. Also have some other illiquid assets which could be worth more or less.
First I started with consulting, then slowly started developing different apps/products/services, and funded the development from consulting/contracting income. Soon the products themselves gave me 2-3k/month, and I didn't need to do that much consulting any more. As Bitcoin came, I already had some money to invest. I lived very frugally, and invested heavily in Bitcoin when it was around $10 or something. Also I have invested in stocks/ETF:s/etc all the time but those play pretty minor role. Mostly got one thing right.