If you have any suggestions for resources, feel free to share them in the comments, and try to provide descriptions of your resources too. Make sure to also upvote the ones you find useful!
The International Phonetic Alphabet. You don't need to know the IPA to make your own conlang, but it's a great way to refer to the sounds that you might include in your conlang.
The Index Diachronica. It lists sound changes by family and sound, so if you're evolving your conlang from another, it gives you a good idea on what would feel natural
Lexiconga. An easy way to store your own languages' lexicons.
625 Useful Words. A list of 625 useful words to add to your conlang's lexicon.
A Conlanger's Thesaurus. A big lexicon of all the words that you could possibly want to have in your conlang, ordered by subjects and connections between words.
Swadesh list. A list of words used to compare langauges. (Wikipedia)
3.1. Appendix. List of swadesh lists for many different languages. (and even some conlangs!)
Kinship Terminology. One of the easiest ways to introduce non-English flavour to your conlang.