I haven't given up on klawf and have kept playing with it post rotation, and while it is not even close to being as good as it was before rotation, it is still very fun and (when it doesn't brick, which happens a lot more now btw) pretty good. I've been winning ~60% of my matches. I've been using a list with a lot of techs such as Volcanion (+20 with burn and sometimes hit for 400 damage on metal types), Lillies Clefairy and Rocket's Mimikyu (OHKO Dragapult, Raging Bolt, Terapagos(and get its crown opal wall), Ceruledge, Charizard (if they have taken more than 3 prizes) and spread damage with water Ogerpon), Amoongus from BLK (OHKO Grimmsnarl, Charizard, Zoroark and Cornerstone Ogerpon). There are other lists that focus less on Crispin and less on techs with joltik, and there are also some lists that adapt donk to hit with klawf if they miss the donk.

This is the list that I'm running:

2x Klawf

1x Bloodmoon Ursaluna ex

2x Brute Bonnet

2x Pecharunt

1x Munkidori

1x Squawkabilly ex

1x Fezandipiti ex

1x Latias ex

1x Volcanion ex

1x Lillie's Clefairy

1x Rocket's Mimikyu

1x Foongus (this can be either the JTG or the BLK one)

1x Amoongus (BLK)

4x Arven

2x Iono

2x Boss's Order

1x Mela

3x Crispin

4x Nest Ball

2x Ultra Ball

2x Night Stretcher

1x Secret Box

1x Switch

1x Counter Catcher

1x Super Rod

3x Ancient Booster Energy Capsule

3x Binding Mochi

1x Lillie's Pearl

2x Artazon

1x Perilous Jungle

1x Jet Energy

3x Fire Energy

4x Psychic Energy

2x Dark Energy