Biography
Jerry Nelson (July 10, 1934 – August 23, 2012) was an American puppeteer, best known for his work with The Muppets. Renowned for his wide range of characters and singing abilities, he performed Muppet characters on Sesame Street, The Muppet Show, Fraggle Rock, and various Muppet movies and specials. Description above from the Wikipedia article Jerry Nelson, licensed under CC-BY-SA, full list of contributors on Wikipedia.
Known For

The Muppets
Telethon Announcer (voice) (uncredited)

The Dark Crystal
High Priestess / Dying Emperor (voice)

The Muppet Christmas Caro...
Tiny Tim Cratchit / Jacob Marley / Ghost of Christmas Present / Lew Zealand / Ma Bear / Mouse / Mr. Applegate / Penguin / Pig Gentleman / Pops / Rat (voice)

The Muppet Movie
Floyd Pepper / Robin the Frog / Crazy Harry / Lew Zealand / Camilla / Dr. Bunsen Honeydew (assistant) (voice)

Muppets Most Wanted
Announcer (voice) (uncredited)

The Muppets Take Manhatta...
Camilla / Lew Zealand / Floyd / Bear / Chicken / Crazy Harry / Dog / Dr. Julias Strangepork / Granny / Penguin / Pops / The Count (voice)

The Great Muppet Caper
Floyd Pepper / Pops / Lew Zealand / Crazy Harry / Louis Kazager

Jim Henson Idea Man
Self (archive footage)

Muppet Treasure Island
Statler / Blind Pew / Mad Monty / Floyd Pepper / Lew Zealand / Tomato / Pirate / Skulls / Trelawney's Butler / Screaming Cat (voice)

The Adventures of Elmo in...
Count / Pestie / Grouch Mayor / Grouch Cop (voice)