1) Walmart (or other) companies pay so low wages that employees are eligible for food stamps or other subsidies. This is utterly outrageous and should be a criminal offense - at least, states should be allowed to claw back the assistance costs plus a 200% fine from the company to discourage this behavior.
2) Environmental subsidies: Government pays subsidies to companies (or private persons) to install new environmentally-friendly technology which is (thanks to being new) too expensive from an ROI viewpoint. Germany did this with solar and basically kickstarted the market for home solar, USA did the same with the incentives for Tesla and other e-vehicles. Obviously, these subsidies are fine as they lead to further savings or environmental goals down the road.
3) Government gives tax breaks to companies for relocation/creating new business: these are the most contested probably as multinational entities (hello Amazon) often enough abuse them for their own profit only. Done right, however, this form of subsidies has a positive ROI as a new business pays local taxes as well as its workers, who additionally provide purchasing power in their communities.