I've got 5 ratchets that have a flex of some sort
Snap-on 1/4 drive swivel head with grip THNF72
it fits in some tight places but the swivel design seems to absorb some torque. I'll have issues breaking a nut/bolt loose, switch to my F80 3/8 ratchet, which is less than an inch longer, and she pops free
Snap-on 1/2 drive 18" locking flex SX80B
love this ratchet
EZ Red 12" long 1/4 stick
one end is 1/4 square drive, other is 1/4 bit holder, both ends have locking flexes (can't be left unlocked). They also make a version with 3/8 and 1/4 square drive ends. I sometimes forget I have this tool... and the backdrag kinda *****
SK 3/8 drive 10.9" flex round head 45183 with the double tooth mech installed
love the old style and the feel of the knurled handle. I bought it for at home but took it to work to try it out... it's still at work

but the head is big and bulky, doesn't fit in tight spots
Matco 3/8 drive 12" locking flex with grip
was my go to 3/8 ratchet, now it needs another rebuild and the grip looks like **** but I no longer have a matco guy/truck that stops by

it does give me an excuse to buy the snap-on FX80A locking flex ratchet that I've been wanting
The snap-on locking flex can be left unlocked but it's easy to accidentally bump the button back into the locked position
I wrench professionally, so I go for easy warranty and high quality on heavy use tools... But for a budget, I'd look at the tekton flex head or an older gearwrench 84 or 90 tooth locking flex ratchet, the gearwrench's use a similar design to matco for the lock