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AD/lvl marks shouldn't be overlooked either after you have both penetration sets. Certain champs that scale really well with AD (RIP old Kat), or where you can expect to see early pen built anyways, or kits with inherent penetration, these runes are actually more cost-effective per stat per rune slot. Others and I run them on AD Malz mostly, but I could see other champs use them effectively like Sivir, Darius, Talon, Wukong, etc.
Hybrid pen marks are good depending on the champ since you don't take a big loss in one pen and get both pens. They also has some value to Sheen/Lich Bane procs on APs as the damage is physical. Sona, Malphite, Akali, Jax are just a few options depending on your build. These runes are really expensive though.
Other champs scale better with AS marks like Vayne and Kayle.