What can I use instead of ramps?

Bärlauch is wild garlic / ramsons and from the same family as ramps, not quite the same but similar enough to substitute – at least where just the leafs are used. I am not sure if Bärlauch also has those tiny onion-like bulbs that you find on ramps, but if you forage it yourself, just check :)

You might be able to substitute wild garlic leaves, which I think are more common in Europe. This article actually says ramps are called "wild garlic" in Europe, but I don't think they're the same thing (two different plants). Since it conflates the two, I'm sure one would be a good substitute for the other!

http://germanfoods.org/german-food-facts/wild-garlic-barlauch/

We need Maedl to translate!

Depending on what you're doing, you could use a bit of garlic chive/buchu. My understanding and experience with ramps is that they're oniony, with a bit of a garlic kick. Other than that. I don't think standard leeks are as aromatic, but in a pinch leeks or spring onions could work.

Ramps are wild leeks. My German isn't good enough to know what the translation would be. But you could substitute leeks or even green onions/scallions in a recipe. If you use scallions, you'd have a milder outcome than with ramps.