SMC Pentax-A 2.8/24
SMC Pentax-A 4/24-50
Tokina 2.8/24 (PK-A mount,
not RMC!)
Sigma 2.8/24 II
I don't own the Pentax zoom, but heard multiple times the IQ is excellent (prime like). The older M version is said to much worse. On German eBay it can be found 5-6 times a year, auction prices between €90 and €150. But I don't know whether it is better than the D-FA 24-70, which you don't like.
Mind the Tokina mentioned is NOT the "RMC" one, but a newer design (with "A" contacts only). This one is VERY seldom (maybe once a year or less often on German eBay), and mostly not expensive. I guess people think the missing RMC designation makes it a less desireable itmem; so they miss what a gem this lens is. In our lens database this version is not mentioned, just the RMC one. But one of the reviews (member
pericombobulation) is about it. I own both versions (the older one has now developed a stuck aperture), the difference in IQ is big.
The Sigma seems to have extreme copy variation. If you read reviews (on PF and elsewhere), you will find everything (excellent, paper weight, and anything in between).
If you wonder why all these are MF: I don't own many AF lenses.