Where to find LP clamps?

...so, you want to find first clamp and than match the turntable??::))

Don't go for Sota or VPI clamp that realy can only make the record placement worse than it used to be since they're too heavy.

For a proper clamping you need to very slightly couple the record to the platter or mat (I would recommend a donut-shape mat to use with clamp)

I have Michell Gyro SE turntable with Michell clamp that gives me an extra flexibility either to firmly couple the record to the platter or just place it without locking that couples it slightly or not to use it at all. I all three different situations you should realize that the sound is different.
The first described situation I use on extra bright vinyls with poor mastering. If I lock the clamp my record will be firmly coupled to the platter and there will be a significant roll-off of high freequencies with even vast sacrifice of details. If I use no clamp I get airy presentation that is very suitable for small bands. In second case unlocked Michell clamp adds a tonal control that I often use for sophisticated instrumental and electronic music which is probably 70% of my entire collection.

I might argue on that since Michell uses an acrylic platter that I cannot consider it "springy" or unsupported and the clamp realy works best if only applied without locking on the Michell. The same I can say about Oracle tables where you should only slightly screw the clamp to touch the label. Simply saying when you couple a record directly to the platter the minimal clamping is sufficient and best.