Fire Emblem was released in 1990, so that's a game and a franchise turning 30 next year.

Phantasy Star 3 turns 30 in 2020 and although it's the black sheep of the traditional games, I still really enjoy it.

SaGa 2 (also known as Final Fantasy Legend II) also turns 30 in 2020, in fact the SaGa series itself just turned 30 on the 15th.

And an old childhood favourite of mine, Nintendo World Cup was also released in 1990.