Infinitely scaling
So we've got
for Physical damage
for Health
for Magic Damage.
Can we have a champion that infinitely scales Movement Speed?
Not because it'd be terribly useful, but because it'd be funny as hell.
Late game Nasus can one-shot a tower, late game Sion can take a tower out while dead, late game Veigar can one-shot a carry.
Late game [insert name here] can run around the enemy nexus and back before Homeguard ends.

is one of several champions that can, in theory, infinitely increase his stats (in his case Meeps attack damage).
is one of several champions that can, in theory, infinitely increase a stat by using an ability. Kindred can continuously add Physical damage to its basic attacks with the Mark of the Kindred.
is one of several champions that can, in theory, infinitely increase a stat by using an ability. Thresh can continuously add armor and ability power with his Damnation.