Welcome to the forum.

I have yellow bearded iris which is budding right now planted among some tulips. The only problem is iris clumps get really big so you have to divide them every 3-4 years. But they bloom right about the time tulips fade.
If you don't mind using pansies they come in all colours, so you shouldn't have a problem finding yellow ones. And they self-seed so you'll get volunteers.

Do you know if pansies bloom over a long period or short? Will they continue for most of the summer? Thank you so much for your input!

From my experience, pansies bloom until about August, then their life cycle as biennials winds down - their seeds will have self-sown everywhere and you'll have to wait til next Spring to see new vibrant plants.

Annuals in front of, or in among your spring bulbs can also hide their dying foliage. I plant nasturtiums every year in the front of one of my bulb beds. They bloom so profusely by the end of summer, they're quite spectacular.

(Sorry in my earlier reply I suggested irisis but hadn't noticed you've already got them and they were already fading - I'm in a colder zone so things bloom later here)

I've also overplanted with pansies, but for me they last until after the first frost. I think the nasturtiums is a great idea, but I would still need something for inbetween the bulbs and the nasturtium blooms (LOL, I love pansies, but I think I have enough so I'm looking for another plant to use in addition to)