If you want to stick to tried-n-true, do a web search on wine growing regions that do a lot of blending, like Bordeaux. Bordeaux blends Cabernet Sauvignon, Cabernet Franc, Merlot, Petit Verdot, Malbec, and Carménère in a lot of different configurations.
Rhone includes Syrah, Grenache, Mourvedre, and a bunch more. Italy is a different mix of grapes. In Chile they mix-n-match the above to produce very successful wines.
Honestly? I don't think you can go wrong with French, Italian, and Zinfandel. Certainly others as well, but the ones listed have commercial success.
@DPCellars has a successful blend I would not have thought of, Cab & Pinot. The old rules are tried-n-true .... but there is room for new rules.
@Ajmassa's advice is probably best -- make separate batches of whatever catches your fancy, and do bench tasting to identify the blend you like best. Whatever is left after you make your primary blend should be good on their own. Or mix the remainder together to produce a Frankenwine blend. It might surprise you.
I'm planning a Bordeaux blend this fall -- going primarily Merlot, and planning to add at least 1 lug each of Cabernet Sauvignon, Cabernet Franc, Petit Verdot, and Malbec (assuming all are available in our order). I'm looking at the ratios that various Merlot-based producers use to formulate my plan. I don't have room to make enough of the blending grapes in separate batches of each, so it will be a field mix.