Hi,
I've always had this kind of fungus here and there in my lawn and had not paid much attention to it. But this year it seems to be taking over my garden. Would you think I should do something about it?

How is it taking over your garden? Does it actively harm your plants?

I live in a temperate, rainy, area, so I notice lots of fungi...I usually just leave them all alone.

The fungi are there most likely
because of shallow buried wood underneath the lawn. The wood is being broken down by the fungi. Then they throw a fruiting body up through your lawn. Fungi would not be feeding on the living lawn!
What you have is natural, don't worry at all.
If you had a good deal of rain lately, that could be a contributing factor to see more of it.

Check the type, it looks edible.
Do not worry about it.

OK, so I will continue to disregard them. Thank you all!