Steelix can't learn Iron defence
Glalie can't learn Mean look
Regirock can't learn Rock blast
Electross can't learn Thunderfang
Rampardos can't learn Head smash
Scolipede can't learn Rapid spin
Gengar can't learn Nasty Plot
Regiice can't learn icicile spear
Pic related - This cancers can learn slashing moves while having no claws, while Luxray line can't learn any, even if the dex entry mentions it.
Its sad to see that Pokemon could be simply better game when they would fix movesets and abilities to match the pokemon better.