I don't want to get into trouble for advertising, so I won't provide links, but Lee Mendelson Film Productions has been releasing new deluxe editions of Charlie Brown specials, as well as scores from specials that have never been released, for a bit over two years now. So far:
"It Was a Short Summer, Charlie Brown"
"You’re Not Elected, Charlie Brown"
"It’s the Easter Beagle, Charlie Brown"
"Be My Valentine, Charlie Brown"
Jazz Impressions of a Boy Named Charlie Brown (expanded and remastered)
"Charlie Brown Thanksgiving"
"Charlie Brown Christmas" (definitive new remastering version with additional material)
"It’s Arbor Day, Charlie Brown"/"Charlie Brown’s All Stars" (EDIT: due March 20)
And one exception from Kritzerland Records:
"A Boy Named Charlie Brown"