[slothtrop]

This depends on the market and the trade. Not all are equally competitive. Might have to investigate your area but look into plumbing, HVAC, carpentry and others. If you don't care about the nature of the work, go with the most promising prospect. If you do, then explore them, watch youtube accounts of the job, etc. Personally I think the downside is longer hours (typically) and often shift-work.

Since you're asking on HN I expect you're not averse to programming either. Can be competitive at Junior level. Take a free course at freecodecamp or whatever, will give you some idea whether it's worth pursuing. People will often say "contribute to open source" but without a frame of reference you'll just feel lost, so either take a course or start your own project first.

There are some other high-turnover gigs like corrections. I don't know if I'd recommend this, but it wouldn't take you long to get in. Expect overcrowding, violence, and stress.