~_~ I can tell you the ones you can't catch in Fire Red (compared to Leaf Green).
Bellsprout/Weepinbell/Victreebel
Magby/Magmar
Slowpoke/Slowbro/Slowking
Sandshrew/Sandslash
Vulpix/Ninetales
Pinsir
Staryu/Starmie
Azurill/Marill/Azumarill
Misdreavus
Sneasel
Remoraid/Octillery
Mantine
Pokemon like Lugia, Ho-Oh, Deoxys, etc. aren't exactly "catchable" without a Nintendo event.
I can't make a comparison to Emerald though.