DIY: slim jim, J pole (https://m0ukd.com/calculators/slim-jim-and-j-pole-calculator...) or quarter wave ground plane (https://m0ukd.com/calculators/quarter-wave-ground-plane-ante...). A slim jim made from 450 ohm ladder line and rolled up for storage, hoisted into a tree by a cord, is a favourite. A NanoVNA will help a lot while building any of these.

Commercial portable: Nagoya NA-771 (beware clones)

Commercial fixed: Diamond X30, X50 or V2000 colinear.

With any upgraded antenna on a receiver with little filtering like the Baofeng, you may deafen it into hearing no wanted signals if operating it in an RF-hot environment.

Don't transmit without a licence.