Depending on the size of the rocks and number of varieties you want to have, I can suggest a LOT of different varieties for you. I'll keep budget in mind, 99% of the frags I'm going to suggest will be under $150 for a couple polyps and I wont suggest anything bigger than your average zoa! I think all of thse will also grow well together as a garden, Ill make a note of any that are a little faster growing but none will be invasively fast or weedy.
Eagle Eyes- very cheap, bright, and TINY! A little faster growing but given their diminutive size, its usually okay
CK Bitcoin- Pretty cheap and available, also yellow but it has some rainbow hues. Normal size
Chucky's Bride- A little more expensive (around $80 usually) but a very pretty bright pink and yellow zoa. Average size
Bubblicious- Chucky's Bride not quite right? Try Bubblicious! The pink is a little deeper and the separation between the yellow mouth and pink outer ring by the dark purple/black makes for stunning contrast, especially in a colony setting
Evil Eye (zoanthids.com)- Not many of these available on the hobbyist market yet but they are a stunning shade of orange! Normal size zoa
Bowser- normal size and a gorgeous red-dominant rainbow! If you want a cheaper alternative, candy apple reds look similar
Daisy Cutter- Also known as JF Star Gazers or Pinwheels, every zoa garden needs a good pop of blue! The white on these bad boys also shines under blue lighting and theyre pretty accessible and cheap these days. A little bit of a faster grower.
Queen Strat- A beautiful light olive color under the right conditions and they're a little smaller than the average zoa. I love these guys!
Darth Maul- Can be substituted for nightmares or illuminati. Black background with a TON of red speckling throughout. Adds beautiful movement and price differs based on what variety you buy but they all look pretty much the same especially in a garden setting
Rose Nebula- You gotta have your magenta/pink to round out your garden! These are a great option due to their speckling and wide availability.
Purple Nebula- If the Rose Nebula didnt scratch that itch for some purple then these sure will! Seller on here Mateusz has these guys for a very nice price and even though theyre a little bigger than average, not even WWC's purple monsters can touch these guys!
Lilac Wine- And finally, if you really like pink and red together, these guys take the cake for me! Along with their gorgous seafoam green/ teal skirt these make a gorgeous addition to any zoa garden and their unique coloration means that they will look good next to just about every zoa out there! I especially like them near Queen Strats and Chucky's Bride/ Bubblicious. Pic by Mateusz
I think I covered pretty much all of the major color groups here. If you have a favorite color you really want to fous on (either because you just like it, it makes your sps pop, or it looks the best under your lighting) please just respond to this post so I see it and I'm happy to suggest more! I think all of these would look very nice together in a zoa garden and I made sure to include very busy ones and plainer ones so your eyes dont have a heart attack. Happy reefing and your garden is gonna be the talk of the forum!