MythicBotany is a mod that expands botania a little bit. Some of its features are listed below:

The mana infuser: An upgrade to the terrestrial agglommeration plate that requires gold an shimmerrock underneath and besides Terrasteel allows to create Alfsteel.
Alfsteel: Made like Terrastell but with alfheim resources. Can be used to create a better armor, pylons and other things.
Dreamwood Wands: You can now make wands of the forest from dreamwood
Some new flowers:

Wither Aconite: Creates Mana from nether stars
Exoblaze: Fills the fuel of brewing stands with mana
Hellebore: Stops piglins and hoglins from zombifying in the overworld
Aquapanthus: Fills petal apothecaries and cauldrons nearby.
Raindeletia: Creates mana when it's raining. Must have a clear view to the sky. Place it on vivid grass or enchanted soil to make it produce more mana.

It also adds an alfheim dimension and some content from the norse mythology

Everything can also be found in the lexica botania.

To further improve the alfheim dimension, check out Feywild, a land of magic and fey. It adds a config option that its features spawn inside the Alfheim dimension which can greatly improve alfheim and make it even more worth travelling there.

If you prefer a video showcasing the features of MythicBotany: AA Gaming made a very good and detailed mod showcase: