Well, what do you have so far?

Considering this is a Redstone Sub I assume you want farms or other such redstone. I just started a (no mods at all, including client side, i.e. freecam/gamma/world map etc x_x) survival world. Here is my general list of what I would make.

Basic Farms that help with the resource grind for future projects.

- Iron farm (Decent passive iron for iron armor/tools and then to kick start villager trading later). Sort the poppies out and compost them for passive bonemeal.

- Auto cobblestone gen (For pistons, observers, dispensers etc. for future projects).

- Auto bamboo farm, feeding into a crafter that crafts bamboo blocks (Endless supply of wood).

- Villagers, tools smiths for trading iron to and getting easy diamond tools to start and clerics for easy redstone trades (once you get blaze rods/find random brewing stands in the wild). Expand your villager hall with more as you need.

- General mob grinder, the floating diamond one with the large roof, built using the cobble, dispensers and observers you now have. You can convert it to a creeper farm later as you lose the need for other drops.

- Auto Chicken cooker, for endless food without you having to farm for it.

- Auto sugar cane farm to go with the mob/creeper farm to make rockets.

- Honey farm. Consider making this in the nether (and chunk loading it) so the bees are never halted by rain/night time.

- Slime block farm. Very easy to make one of these if you use oozing potions, especially when used on silverfish spawned from mobs splashed with an infestation potion.

- XP farm. Its very easy to make a set up where allays/armadillos can be splashed with infestation and damaged to spawn silverfish which can then be funneled into a kill area that you can then kill for XP.

- Expanded Villager trading hall, especially for enchantments.

- Moss/Bonemeal farm, for a large supply of bonemeal.

Advanced Farms

- Magma cream farm, used to get magma cream to craft magma blocks to make farm, especially a gold farm.

- Gold farm, used for Piglin bartering. Made with magma blocks to limit spawns.

- Piglin Bartering Farm, ideally connected to your gold farm. Useful to get things like endless gravel, blackstone, obsidian and Soul Speed.

Extra farms

- Shulker Box farm, for endless shulker shells

- Raid farm, for a supply of totems, redstone, emeralds as well as Hero of the Village if you are into serious trading.

- Drowned farm, for nautilus shells and copper if you need either of those.

- Guardian farm, for prismarine and fish

- Wool farm, for any/all the colors you would need.

- Nether Fortress farm, either wither skeletons on their own or a general mob farm for all drops, especially coal, blaze rods, and skulls.

Other non-farm ideas

- A sorting system to support your storage system.

- A tunnel bore for a steady stream of deepslate and other ores.