An invisible ink card is a special variant of the regular version, that basically looks the same, but is exclusively foil and has extra in-universe text from the investigative crew taking notes about the character
We play Rydia early enough that we can ramp and use Rydia's landfall ability to fill the graveyard with Saga creatures by discarding them
Alpharael lets you draw two cards, then discard twobut if you control an artifact, you skip the discard
Modern keeps the price somewhat high, but it's worth it since you now have the power to cast auras and equipment at flash speed and place equipment on creatures for free on ETB
And once again, Zinnia comes along and lets you have two of these Otter Artificers thanks to the Bird Bard bestowing offspring to all of its loyal listeners
As such, every kind of deck archetype is playable, and there is no shortage of them