Not sure who the main 7 leagues are, I presume England, Italy, Spain, Germany, France, Netherlands and Portugal, so here are my suggestions:
RSC Anderlecht
Fenerbahce
Sparta Prague
Glasgow Rangers
FC Basel
Red Bull Salzburg
Rosenborg
Olympiacos
FC Kobenhavn
Dynamo Kyiv
Crvena zvezda
Dinamo Zagreb
Lech Poznan
Malmö FF
FCSB
Ludogorets