Hi! I will update this thread regularly with new references. Here’s a few links to get started with Toki Pona:

Main resources

Official website
Toki Pona: the Language of Good: official book by Sonja Lang (also available in French)
Toki Pona lessons by jan Lentan (12 lessons, 10 words per lesson)
Toki Pona glyphs lessons by David A Roberts (purely visual)
Toki Pona Cheat Sheet

Glyphs and fonts

Anki: spaced repetition system + decks
Glosbe dictionary: Toki Pona/English dictionary with many compound words
ilo: Toki Pona translation tool by dustin
Kommit: general flashcard-based memorization tool by Rosano
kulupu.group: Toki Pona wiki by c0debabe
lipu nimi pi toki pona taso: dictionary written in sitelen pona by David A Roberts
nimi ale pona: lexicon including non-official words
Org Flashcards: general spaced repetition system for Emacs org-mode by @l3kn
pimeja: interactive dictionary with official English and French definitions by @ice
Practical Toki Pona Dictionary by @soweli_nata
Toki Pona Parser by jan Lope
Toki Utala: Toki Pona vocabulary mobile app by Increpare