Big union trades:
Carpenters: Kicked out of the major union org. They speak of themselves as "builders" compared to "trades". Many are carpenters until their body gives out, then they become general contractors. Commercial carpenters are typically those who build the concrete formwork or they erect metal studs. Resi carpenters do custom home builds with actual wood.
Subfield of Carpenters: Drywallers, Mudders, Tapers. Huge part of carpentry. Hack work typically although some guys better than others. Work can be found anywhere.
Ironworkers: Workers who install field for high rises. Good union in my area. Hard work, especially rod busters. Also involved with rigging.
Electricians: Trade which stays on the job the longest. Pretty much the "brother" of plumbing, from the varied materials encountered, the scheduling on new construction. Mostly new construction. Can't figure out what works? Demo and install something new.
Concrete workers: Hard as hell, pay is better now, work in teams.
Mason workers and bricklayers: Hard as hell, pay is not great. Work can be aesthetic.
Painters: Overhead spraying everyday
Operators: Good pay, operate heavy machinery
Plumbing: The prototypical trade. Very similar to electrical work. Sees more type of work in service, residential.
HVAC and Duct Workers (Sheet Metal): Primadonnas on the job. There's two types. Those who install in the field, and those who work in the shop. Much of the work in the field is pulling measurements and installing prefab. They typically dominate overhead work and ignore other trades. They don't do underground work, they typically don't do slab on grade work. HVAC is refrigeration which can be separate, but all encompassing in running copper line set, and huge part of them are controls, startup, and building automation
Fine Carpentry: Many fields. Could be door guys, cabinet makers, or just installing trim. They're in the field as much as they're in the shop. Delicate, fine, detailed work.