Fuse trim is one you can do anywhere (but maybe or maybe not
"production qualified"). Poly or aluminum neck and a bond pad
per "cut" (unless you go to on chip trim switches, which can be
even larger than a bond pad and then you need a programming
-interface- as well).
NVM controlling a switch FET gate is another common option.
Not my fave as in some applications NVM is not nonvolatile, and
you may be pushed onto a more expensive flow to get the EEx
element.
Zener zap and gate zap are also nonvolatile (OTP) options,
can work as a direct element or a gate control.