Yeah, that's a really tough issue. We never let our private tutoring students use non-official verbal materials under any circumstances, so we're really careful about how we use the OGs, the official practice tests, and the GMATPrep Question Pack. In the early stages, we tend to assign lots of LSAT for CR and RC -- if you're interested,
here's a long-winded article about using the LSAT for GMAT studies.
SC is a trickier thing. For CR and RC, there's a nearly limitless supply of LSAT questions, but there's no "non-GMAT" alternative for SC. So with our private students, we start with RC and CR, and then once we see those results stabilizing at a level that makes everybody happy enough, we add SC to the mix.
For whatever it's worth, there are also ways to be creative about stretching your verbal materials. For example, if you're using the 2020 or 2021 OGs, you could reach back and do older editions (say, 12th edition OG + 2nd edition verbal guide), and about half of the questions will be new to you. Similarly, once you've exhausted the first two mba.com tests -- and you're SURE that you won't take them again -- you could do all of the verbal questions from those question banks.
So basically: LSATs first for RC & CR if they aren't too hard for you, then transition into the GMAT OGs, and be ready to use older editions if you need to.
I hope that helps a bit!