If you're a software developer, you can make money offering plug-in development for WordPress website owners, there are a lot of demands for Plug-ins that do basic stuffs, if you can find a way to talk to website owners and find out their need you will be able to build a cool business for yourself.
You can also sell your Plug-ins on websites like Envato too, the cool thing about Plug-ins is they provide you with monthly recurring revenue you can rely on and if you're good with marketing, you can create a branding out of this and make it a standard business, that's exactly what OptinMonster did.
You can also sell your Plug-ins on websites like Envato too, the cool thing about Plug-ins is they provide you with monthly recurring revenue you can rely on and if you're good with marketing, you can create a branding out of this and make it a standard business, that's exactly what OptinMonster did.