Best pick for beginners?

why don't you just grab the four four a dollar picks in the jar near the check out counter of most music stores. They typically are medium. then, pick up a few thinner picks, and one heavy one.
try them out. listen to what sound or tone they produce and how they feel.
that is the best way.
I ended up settling for the mediums. four for a dollar. 44 years later I like what they do.

I'll vote one's thumb.

Guitar picks are really cheap, maybe $.25 to $.50 each. The best way to know which kind you like best is go to a music store and buy $5.00 worth of picks of different thicknesses, sizes and materials, take them home and try them out over the course of the next several weeks or months as you learn to play. There is no right or wrong answer to this question, its all a matter of personal preference. You'll figure out for yourself which you like best.

My advice, for what it's worth, would be to try and get used to using your fingers - without a pick - as well as experimenting with the various pick sizes and gauges. I can't remember the last time I actually used a pick....I keep my nails on my right (strumming/picking) hand quite short, they're just barely visible over the top of my fingertips when looking from behind. This way I can change from strumming to fingerpicking or soloing without any pauses.....and it's a lot easy to fingerpick with a thumb and three fingers (forget the pinky) than is to play with a pick held between thumb & forefinger to pick bass notes and only two spare fingers for the top three strings!

:D :D :D

Vic