My appraisal went up 20%

For Sales Comps: Best to ask a local realtor to help you find some.

But your best bet is to get on the county appraisal districts website, use the interactive map and check out what some of your neighbors have had their properties valued at.

Very few homeowners will have success protesting based on sales comps because of this market. But you are also allowed to protest based on unequally assessed CAD values compared to your neighbors.

So a good example if you are struggling to find adequate sales comps that help support your case like myself, you'd try to find 3-5 properties around you that are very similar (+/- 10%ish square feet, similar conditions) and argue from the stance of "why is my property valued higher, but the house across the street that's almost the same is lower".

I also want to point out that if you don't feel comfortable protesting, you can absolutely hire someone to do it for you. But usually you have to file the protest by May 15th unless otherwise stated by your appraisal district.