I caught one of Kirk Hammet's when he threw it to the crowd, and James Hetfield looked down at me and my buddy and threw his pick straight at me. Rick from Cheap Trick tried throwing me a pick about 5 times before he finally aimed right and didn't hit the security barricade
Most recently, the girlfriend and I both got picks thrown by Ghost's guitarist with the white RD.
I was lucky enough to pickup some from Kerry king, rich ward, dimebag, Wayne static, Kurt from down, neurosis, max and andres, logan and rob (mh),from coal chamber.
I did not "catch" these picks but have picked them off the ground between the stage and the security barricades because the guitarists did not throw their picks far enough into the crowd.
One pick from Trey Azagthoth from Morbid Angel on their "Gateways to annihilation" tour.
One pick from Eric Hoffman from Deicide on their "In torment in Hell" tour.
I did not catch these but were given to me from my friend who was standing closer to the stages.
Drum stick from Paul Mazurkiewics from Cannibal corpse on their "Vile" tour.
Two picks from Tom Araya and Jeff Hanneman from Slayer on their "Diabolus in musica" tour.
I've never caught a pick, but Eric Sardinas did give me his Dunlop Preachin' Pipe signature slide after the gig. He was opening for Vai, and most of the crowd were old guys not getting too excited about Sardinas, no doubt saving themselves for Vai, whereas I was going wild all night. Being in the second row, about 8 foot from the stage, Eric pointed at me, tossed me the slide and shouted "Thanks!" before strutting off stage. I was so chuffed with that. It's a properly abused slide, it's absolutely covered in gouges from his strings, they start off so shiny and smooth too, so I think it must have been used for a while before he gave it to me.
Unfortunately, I'm a complete cack hander at slide and other than using it for 5 minutes here and there I've never done much with it. It has got some serious mojo though.
I also got an earplug from Brian from Black Dahlia Murder the first time I saw them. I still have it.
My brother got a Stu Hamm bass pick (which is handy as he plays bass and Stu is his all time bass idol) which Stu tossed to him when we were in the front row at a Satch gig. It's a B3 one, from his tour with Billy Sheehan and Jeff Berlin, it's a white triangle pick, pretty thin, with a green B3 logo and Stu's signature etched on it. I was really happy for my brother to get that, because he has been a massive Stu fan since he was about 12 years old. He was very active on Stu's forum when he used to have one, and did talk to Stu by email in the past, and I know they still exchange messages on Facebook from time to time.
Went to see smashing pumpkins this past tuesday, and Billy Corgan was throwing them out into the crowd at the end of their main set. one slipped RIGHT through my hands and I lost it in the crowd
I was watching Judas Priest at Roskilde Festival in 2008 and one of their picks flew through the hit and hit me in the face! completely unaware as to what it was, I looked down and saw the pic on the floor with the JP emblem on it!
Just as I bent down to pick up my trophy and basque in glory, some fuck pushed me out of the way and took it! Worst feel ever
I've got quite a few things. I've snagged a Fredrik Åkesson pick last time I saw Opeth, got one of Michael Romeo's at a Symphony X show, caught one of Tony Lazaro of Vital Remains picks, and as the Death To All show in NYC was ending Steve DiGiorgio went into his pocket and pulled out a Sadist pick and I ended up catching that. As far as things besides picks go, at the same Death To All show, Paul Masvidal threw his water bottle and I ended snagging that, and when I saw Decapitated, Krimh's drumstick snapped during Spheres Of Madness and as he switched drumsticks, he threw the broken half he was holding and I caught that (without being stabbed by the broken wooden end haha). Only other cool shit I got from a show was I got the guys from Cynic to sign my physical copy of the Carbon-Based Anatomy EP for me when I saw them, and got the dudes from the Faceless to sign my copy of Planetary Duality.
Besides that, on the last night of the first Ophidian Trek tour that Meshuggah hosted, they played Terminal 5 in NYC and at the end, Haake pulled off his drumheads and began throwing them into the crowd. I was inches away from snagging a tom head until someone got there right before me...