Oh wow! Lemmee think back here.
If you're talking rock and roll,then my first in 1979 would be "Sessions Records:40 Golden Hits". I've talke of this before but,overal,that 3 record set is the one. Lots of great #1 hits and top tens from the 1950s to (1 song from 1971).
For "kiddie" LPs,it would be,"Toys R'Us presents,"A Merry Geoffory (Giraffe) Christmas". A spoken record where actorsd play the family of giraffes celebrating the hoidays. :D Geoffrey's the one you see on signs outside the store. Hoo-boy! :D
My first LP of a recording act was,"Donny and Marie:New Season". Loved 'em..really loved Marie!