A lot of first-edition spells never made it to 3e and beyond. The higher-level spells are particularly wacky and might be fun to drop into in a later-edition game.
LEVEL 6 SPELLS
Glassee: This spell lets you see through four inches of metal, 6 feet of stone, or 20 feet of wood. (When do you ever find a wooden object 20 feet thick?) This is a nice dungeon-exploration spell, an upgrade of level-3 Clairvoyance. Where Clairvoyance is foiled by a thin sheet of any metal or by darkness, Glassee is only foiled by lead, gold or platinum.
At this level, there are plenty of other ways of finding out what's in the next room: passwall, teleportation, disintegration, and rock to mud are level 6 or lower. On the other hand, Glassee doesn't alert anyone on the other side of the wall. The problem is that, since it's a level 6 spell, it's expensive. Even a 20th-level wizard only has 4 level-six spots, and so can be foiled by a dungeon with 5+ rooms.
The obvious way to make this spell useful is to make it permanent, but hold on: the glassteel spell is coming up. We don't want to step on its toes.
Invisible Stalker: If you wanted to summon an Invisible Stalker, you'd normally have to wait until you could cast Monster Summoning VII, a 9th level spell - and even then, you could only control it for half an hour tops. The Invisible Stalker spell is a much lower-level shortcut: it lets you summon an Invisible Stalker and give it a mission of indefinite length. That's cool!
In general, I prefer a spell for summoning a specific creature to a bag-of-tricks random monster spell. For instance, given the choice between a Summon Random Dinosaur spell and Summon Triceratops with a Saddle And The Triceratops Comes With A Barber Pole-Striped Lance And Also A Pair Of Sunglasses, I'll take the latter, even if I'm missing out on a 16.6% chance of a T-Rex.
The Invisible Stalker spell is arguably a better NPC spell than a PC spell. I can see the PCs upsetting a wizard, and then living in fear of the invisible stalkers on their trail. It's harder to imagine the PCs using it, because it moves the action offscreen. Imagine this:
DM: The evil duke has retired to his castle.
FIGHTER: We'll have to assault the castle! We can gain access by fighting our way through the dungeons!
WIZARD: No need! I'll just cast Invisible Stalker every day and send them after the duke. One of them will eventually slip through his defenses!
DM: (crumples up castle map, cries)
Of course, using Invisible Stalker in this way is pretty much equivalent to hiring an NPC assassin, and there are extensive rules for doing that in First Edition, so I guess it's perfectly kosher.
Spiritwrack: This spell has one of the coolest names in D&D. Spiritwrack is an extremely complicated spell for exacting servitude from summoned demons and devils. It could have been a simple spell that specified the chances of enslaving a demon, but it's more than that: it's packed with details, like a little formula for a mini-adventure. The demon's (true?) name must be learned. A vellum document must be prepared, "covered with gold leaf in a continuous border." It requires ink made from powdered rubies and the ichor of a slain demon of type I, II, or III. It ends with a negotiation between the spell caster and the DM playing the part of the demon, with the demon in greater pain each round. It reads as if it were cribbed from Jack Vance or another fantasy author, as it very possibly was.
I'd give this spell out as treasure in any D&D edition, and I wouldn't change a thing. I suppose it was left out of later editions because of the Satanism scare: it is probably the closest thing in the D&D books to the demon-summoning instructions so feared by Jack Chick and his ilk.
LEVEL 7 SPELLS
Cacodemon: This is another spell for summoning a specific creature type, like Invisible Stalker - in this case, mid-level demons. It was probably left out of later editions for the same reason that Spiritwrack didn't make the cut. It's got lots of details for drawing pentagrams and lighting 5 black candles and other Satanism hysteria fuel. Other spell components include "mercuric-nitric acid crystals" and alcohol, which are actually the ingredients of a real-world explosive, I think. D&D as Anarchist Cookbook!
Cacodemon is actually a likely prerequisite for using Spiritwrack (gotta summon the demon before you can threaten him). A perfectly reasonable spell for a high-level evil spell caster's spell book. The Christian right has pretty much given up on D&D as a threat, so we can be as occult as we want!
Duo Dimension: High level D&D spells in 1e seem to grow increasingly baroque and bizarre, and lend themselves to more and more outlandish gameplay. This spell lets you become two-dimensional, like a character from Paper Mario. You can do anything a paper version of you can do: pass under a door, stand in front of a landscape to make it a portrait, etc. Furthermore, you're invisible when viewed head-on. Although this spell gives you many of the benefits of improved invisibility (which is normally only available to illusionists in 1e) it seems to me that it's primary a puzzle-solving or outthinking-the-DM spell. With creative interpretations of this spell, you can sneak nearly anywhere.
The spell has a downside: while you can't be attacked from the side, head-on attacks do 3x damage to you. I'd love to see this spell in a minis-heavy game with facing rules. In fact, I'd like to see it at all, preferably earlier than level 11. Imagine this as the signature move of some stealthy low-level wizard: an arcane trickster or even a stealth-domain cleric. It might open up the world in interesting ways.
LEVEL 8 SPELLS:
Glassteel: This is basically the permanent version of Glassee. It's the spell you use to decorate your dream castle. You can make glass as hard as steel. Level 8 is kind of high level for such a niche spell, considering that Limited Wish is level 7, but at least it's cheap: its material components are free, so as soon as you hit level 15, you can upgrade home security by installing bullet-proof windows, you can protect your beakers and vials against falls and explosions, and you can provide your fighter friends with stylish see-through weapons and armor, all for nothing! Considering that it's basically a freebie, it's surprising that more high-level magic weapons aren't transparent: a stained-glass Holy Avenger would be a great paladin item.