Perfect Rhymes (same vowel and ending sound):
* These are very rare and usually only found in technical terms or made-up words.
Near Rhymes (similar vowel sound but different ending):
* Alter
* Walter
* Daughter
* Laughter
Eye Rhymes (spelled similarly but pronounced differently):
* Altar
* Sultra (a slang term for sultry)
Other options:
* You can use words that are related in meaning to "ultra," like "extreme," "intense," "powerful," etc.
* You could use alliteration to create a rhyming effect, such as "ultra-intense" or "ultra-fast."
The best option really depends on the context and what you're trying to achieve.