I have posted a couple of recipes for beef cheek, tongue & tail.
Cheek & tail are both hard working muscles so IMO tastier than fillet,same principle as brisket.
They are dense tight muscles that need long slow cooking. Tail has a lot of connective tissue & fat,cheek a thick line of collagen in the middle .They both taste "beefy" its just a matter of what flavours you want with them.
A braise in a French or Italian style.bacon,root veg,stock,wine,herbs will give you a great winter meal + a great pasta sauce or pot pie with the leftovers.
You can go Asian & poach them then smoke them,I did a TexMex thing a while back.
Tongue is different gig because you can cure it ,smoke it, like bacon then poach it like corn beef or you can do it in the smoker fresh. Its fatty but not greasy makes a great sandwich.
There are a number of posts including a great one by Clarissa aka snorkelling girl.