How can I learn wizard spells as a warlock without multiclassing?

Question

Specifically, I'm interested in Floating Disk, but generic methods are acceptable as well.

Pact of the Tome lets you learn cantrips, but I am interested in levelled spells.

Answer 1

Eldritch Invocation or Feats

If you choose Pact of the Tome and combine it with the Eldritch Invocation Book of Ancient Secrets, then you can start learning Ritual spells including Floating Disk.

Book of Ancient Secrets

You can now inscribe magical rituals in your Book of Shadows. Choose two 1st-level spells that have the ritual tag from any class's spell list.

you can add other ritual spells to your Book of Shadows. When you find such a spell, you can add it to the book if the spell's level is equal to or less than half your warlock level

If you want to use a different Pact, then the Magic Initiate Feat or the Ritual Caster Feat would also allow you to cast Floating Disk as it is a Ritual spell.

Magic Initiate Feat

Choose a class: bard, cleric, druid, sorcerer, warlock, or wizard. You learn two cantrips of your choice from that class's spell list.

In addition, choose one 1st-level spell to learn from that same list. Using this feat, you can cast the spell once at its lowest level, and you must finish a long rest before you can cast it in this way again.

Ritual Caster

You have learned a number of spells that you can cast as rituals. These spells are written in a ritual book, which you must have in hand while casting one of them.

When you choose this feat, you acquire a ritual book holding two 1st-level spells of your choice. Choose one of the following classes: bard, cleric, druid, sorcerer, warlock, or wizard. You must choose your spells from that class's spell list, and the spells you choose must have the ritual tag.

If casting time is not an issue (which is often the case with Floating Disk as it is generally cast outside of combat), then having to spend 10 minutes plus 1 action shouldn't be a problem.

Answer 2

The Magic Initiate feat

Choose a class: bard, cleric, druid, sorcerer, warlock, or wizard. You learn two cantrips of your choice from that class’s spell list.

In addition, choose one 1st-level spell to learn from that same list. Using this feat, you can cast the spell once at its lowest level, and you must finish a long rest before you can cast it in this way again.

Your spellcasting ability for these spells depends on the class you chose: Charisma for bard, sorcerer, or warlock; Wisdom for cleric or druid; or Intelligence for wizard.

Barring any other limitations¹, you can learn Floating Disk. But that would be the only leveled spell you learn via this feat.

Since Floating Disk doesn't have any DC, it doesn't matter that it uses Int for casting, as well.

¹ Limitations as in, "But I want to learn more spells as well," or "I want to switch spells like a Wizard."