Most of these can be adapted for newer vanilla Psi versions and some don't even need Random Psideas to work in 1.12, but this is the situation I'm playing with currently. Massive credit to the Psi Taurus Silver Discord. A few of these spells are from the old Psi Compendium reddit posts especially Math's Compressed "Spells I Always Use" pinned post, but most of the complex ones can be credited directly to TauKinth in the Discord, with some exceptions noted.
Backstory: I decided to do a big update to my 1.12.2 pack The Late Pack and I've been testing by doing hardcore runs. While truly "unfair" deaths are supposed to be avoidable, this pack is normally balanced around the default settings where keepInventory is enabled. As such, my circumstances and the reasons for my spell selection are a bit special.
- Lycanite's Mobs and Ice & Fire mobs: I died a lot.
- Custom mining levels and loot pools: redstone and glowstone are available in small numbers, but diamonds aren't really viable until late game.
- Tinkers Construct, PlusTiC, and Bountiful Baubles: Even if I had diamonds, I can make tougher armor and tools than Psi provides, and I can get immunity to a lot of debuffs around the same time I can start Psi. Spells can be added to tinker tools via a modifier, but not armor. Also, modifiers aren't infinite, so I don't take much advantage of it.
My spell requirements were: All usable on Psimetal parts, All helpful for hardcore survival gameplay, and no spells that I could accidentally kill myself with through not having enough Psi (basically just circle bullets). It turned out that redstone varients of components were generally better. For example, fancy spells with 4 tricks usually had more than 16 complexity, so I wrote those off and went for 3 tricks and 20 complexity as the maximum. Random Psideas adds magazines for spell swapping, so trading a lower socket count for 7 max bandwidth was fine.
Break 2 or 1 - A simple CAD spell directly from the reddit collection. I used it regularly, but half the time I found myself just using the 3x3 spell instead despite the increased psi cost.
Mine or Swap - This one's mine actually. I use it a lot. It's pricey for a simple spell, but it has just enough of a magnet effect, and is great for doing a little quick swapping while base building or to replace sand or gravel when mining without any falling.
CAD 3x3 Omni - Omnidirectional 3x3 "hammer" spell by TauKinth. I used this spell at least 100 times more than any other in my runs. It wasn't until I could finally get materials to make a Tinkers hammer that actually dug fast that I finally stopped using this as my main mining spell, and even then it had it's uses.
Hammer Tool - Older 3x3 hammer spell by Snazzfor use on an actual pickaxe. I haven't actually used it yet because I lack modifiers on my Tinkers pickaxe, and in my case it's more of a convenience thing so I don't have to carry around a hammer in my bag.
Silk Touch - TauKinth again. This is the cheapest and most reliable silk touch spell you can barely cast with psimetal parts. Some silk touch spells use conjure light, which is strangely expensive. This is much cheaper. Others often also have many ways they can fail to harvest the block. Then just end up pushing it around instead. This one only has one circumstance where it fails, that being if you harvest from the side and there's blocks above, below, and in front of the block below it. In which case it gets pushed forward one block and the second cast will succeed. I actually only used it for a little while but only because I have very easy access to silk touch in this pack.
Conjure Light or Block - Placing lights or blocks isn't all that special, but this is an important demonstration of what Random Psideas lets you do. Alternate functions in spells. Saves on bullets and time wasted selecting spells. Suppress Next Trick is a godsend. Macros save on bandwidth, but cost the same complexity.
Bucket or Flint - This is a different take on the above alternate function method. Firstly, the macros going into the vector sum are replaced with the full combination they represent. This takes up more space, but sharing the caster and entity location pieces cuts back on complexity. Dealing with placing fire and water is also slightly more tricky since they replace each other. The suppress trick is handled the same, but applying cosine to the sneak effectively inverses the result for trick: die.
Furnace Circle - TauKinth again. I did NOT use this spell because, as a circle spell, it can easily kill you if you aren't paying attention. However, if you aren't playing hardcore like I am, this is the correct way to cook items with Psi. This complicated version of a simple spell evaluates the smeltable items in range compares them on each loop and then uses a technique called "circle sync" to delay the actual smelting process of each loop until the last cast of the spell. This prevents the spell from randomly smelting the same item twice. Not many items can be smelted twice, but it's common enough to be annoying when it does happen.
Furnace Loop - This is my adaptation of the above spell for loopcasting. I used it a ton in my hardcore playthrough. Yes, using a loopcast bullet makes the spell worse, but with Random Psideas, the total loop count can be controlled. This spell checks the caster's total psi on each loop and stops if it's not enough to cast again. This means you only take damage if you cast the spell when you have less than 300, but more than 0 psi, and even then it's only a little. After running out, normal Psi exhaustion kicks in and prevents casting until your psi is full.
Fog Removal Proj - This is TauKinth's Fog Removal MkIV converted for use in a weapon rather than a CAD. Normally this would be a very stupid idea because you'd get caught up in the explosion... but this is in 1.12.2 where Tinker's Shurikens are very broken and now I can put spell bullets on them.
Sling Loop - by ANT83_4. We had a lot of fun with this one and I used it right up until I had flight. Replaces slime sling (but not slime boots). Fall damage may kill you, but the spell cost never will. Usage: 1. Cast. 2. Optionally, crouch (breaks spell loop) within 3 seconds to reduce distance. 3. Aim. Circlesync technique used to "charge" spell by almost stacking casts. Should be 11 casts, 1 tick apart. This seems to dramatically improve the distance.
Span Spanner Axial - Conjures blocks either in a straight line or a perfect staircase based on the direction you're looking. By TauKinth. He's got a much better version, but tuned this down for me to fit in a psimetal CAD. It requires looking in the general direction you're going while casting, it has to be recast after 100 blocks, and when making an upward staircase, you have to look a bit higher than you'd expect. I used it a few times, but not as much as I expected. The sling loop spell was usually able to handle crossing gaps better.
Span Spanner MkIIc - an alternate, and perhaps superior bridge spell, also by TauKinth of course. This one doesn't have the directional look or timing out downsides of the previous one. Instead of building in increments of 45 degree angles, this one builts as straight a line as possible directly where you're looking. The downside is that if you want a straight line or perfect stairs, then you have to aim your cursor perfectly.
Conjure Prism - This is a protection spell to use as a panic button or for when you need to be afk. The "6,000" duration pieces make the prism last for 5 minutes. Adjust to your preference. There are a few protective spells out there, but none are cheap. This one miraculously protects you from all sides, above, and within by conjuring a 2x2 of blocks centered on you. Conjured blocks do not cause suffocation btw. The only downside is that you must be standing on something. If you're standing on a partial block like carpet or a slab, the prism spawns higher to try and prioritize protecting from above, but if you're falling or sinking, you'll just fall through the bottom. TauKinth put in a lot of hard work with no reward to make this spell for me that magically "bends" lines to place an 8 block cube with only 3 tricks. I didn't use it super often, but was very grateful to have it when I did.