Anubia Nana petite, mosses such as mini pellia, subwassertang, marimo moss balls, I'll look at my tank and get ideas. I built a whole tank on this concept. Mini fissiden's, fuck Java moss and duckweed it's like cancer. Amazon swords are nice and easy if your tank is balanced or any slow grower will get algea.
Edit: Everyone seems to be mentioning loads of slow growing plants which won't solve your issue but cost a lot of money and headache/time.
You need plant growth enough to keep your nitrates as close to zero as possible, then light then nutrients. You can have 100 slow growing plants and your tank will still struggle to function cohesively. Balance, light, nutrients, and plant growth based on livestock count. I run high light tanks and low. Took a lot of learning and money when really it just took education. Followed by the hard path of trial and error to learn. Many people try to combat algea with eaters...
People don't realize how algea works with minimal or excessive nutrient count paired with light. That is a losing battle and the shrimp or fish you bought to eat only fuel the algea growth. I now grow co2 plants in a non co2 tank because I have found the Goldilocks zone for air flow, water flow and balanced the water. All of this is a shrimp tank, with bladder snails, hills-tream loach, assassin snails.
You won't know the nutrient profile of your tank until you start setting a base standard. Light needs a timer be strict ish start at 8 hours and set it to when you can watch the tank, that sets a base line, then nitrates to zero with a single rapid growth plant that's easy to manage, I like floating some hornwort super easy to manage blocks a bit of light to the slow growers and algeas small floaters plants get everywhere when you take some out, then watch for what plant deficiencies pop up as it might not be what you expect in your slow growers as whatever you think you know generally scrap it lol. Adjust slow a little nutrients is alot, more is not better. The smaller the tank the harder to manage consistently as parameters fluctuate so much faster.
What are your nitrates? I managed to find the imbalances in my water and go rid of all my algea issues. I run a high light tank. You need one high growth plant like I use hornwort. It keeps everything zeroed nutrients and nitrates zero because it's a fast growing plant. I leave mine looped a strand around the tank heater and it floats. Within 2 weeks. Algea growth stopped and retreated. I had green dust algea. You can have 100 plants but if theur all slow growers and I'm guessing so then it's not gonna make enough difference. Adjust your light schedule I stick to 8 hours on a timer. Feed less. Add less plant nutrients. Once your tank is balanced it feels so dreamy.
Nitrates are as low as my chemicals will test for, but they aren't terribly high precision. I have small tank, so that is probably a contributing factor. I might try hornwort :)
Algea can't grow if there is no nutrients, and see the goal is to have the plants uptake all the nutrient content so there isn't anything for a 3rd party to consume. Thus you need a plant that is high growth speed which one of the easiest and cheapest to manage and buy is hornwort. Followed by a timed light schedule and I bet your issue will line out. If there is nothing extra for algea to eat it can't survive.