“I love Rioja, what else should I try?”
This is a great starting point. There’s a few things going on with Rioja that are worth exploring.
Tempranillo. The dominant grape in red Rioja, it is often combined with garnacha as both complement each other well. So one starting point would be to hunt down other tempranillo form around the world. Tempranillo is grown in places including other parts of Spain, Argentina, North America, Portugal, and Chile.
Another thing to consider is that Rioja is mostly both oak aged and bottle aged. This gives it certain aroma characteristics of vanilla, earthiness, and then with age, tobacco, leather and more.
I’d try and find an unaged tempranillo to have alongside in a tasting, to see if it’s the grape or the ageing style that you love.