My SIL has been on a kick to collect and source all the dyes in minecraft so she can decorate her base with colored items like concrete, carpet, and terracotta. We recently - finally! - completed that quest a couple weeks ago.
Anyway, she played a bit with colored concrete but the texture of concrete is apparently "too boring" for large-scale construction use so last week I helped her & her husband put together a "mud room", a two-deep pool for turning dirt into mud and a nearby drying rack using dripstone for converting the mud to clay. I also showed her how to set up a lava farm to help fuel the clay -> terracotta firing process. (And bricks.) She's since been happily filling her base with all the colors of terracotta and glazed terracotta.
She also wanted a wool farm but they're not good with the redstone bits for an automatic shearing setup so this week I helped them with that project as well. Of course she had to have one sheep for every color. She says, "it's a sheepery, rhymes with brewery".
Aside: Sunflowers were a pain to find! They can only be found in the extremely rare sunflower plains biome. They produce yellow dye. which can also be obtained from dandelions. However, obtaining dandelions involves bonemealing dirt in certain biomes and hoping you get one mixed in with the grass and other flowers. Double-tall flowers like sunflowers - once obtained - can be replanted in any convenient nearby location and can be bonemealed to produce a copy of the original flower directly. They're also more efficient in bonemeal use, reliably producing 2 flowers for every bit of bonemeal applied. Bonemealing double-tall flowers is therefore the much more desirable method if you're into the dyeing thing. Assuming you can find them! The other two-tall flowers - roses, peonys, and lilacs - are pretty common in forest biomes but the biome where sunflowers grow is apparently quite rare.