Unicode is basically a list of characters that you can use on computers. The code charts offer a full list; if the rest of your alphabet is Latin-based, the various combining marks offer unlimited flexibility, and Latin Extended-B through -G offer many rarely-seen characters, including some never used in actual languages and some only used in long obsolete orthographies.
Making more interesting orthographies can be quite fun and make a conlang jump off the page. I quite encourage the use of ñ and ŋ for the nasal sounds normally associated with them, ʒ or ȥ instead of zh, even ƿ or ȣ for w. But while the first four letters don't really need explanation, the last two would probably make more sense in some sort of historical context.
I'd recommend picking your sounds and then finding appropriate letters for them, instead of the other way around, unless you have a historical reason in world otherwise. I'd also think about goals; if this is a language set in a setting where the writers use the Latin alphabet, most such alphabets use one or two diacritics and often diphthongs where Latin's alphabet doesn't cover it. If this is just for fun, it's a balance of interesting and visually attractive versus ease of understanding versus ease of typing. ñ isn't that far away on any normal system, and any of the other characters is a simple alt-xxxx sequence on Windows. But characters like ȥ, ƿ and ȣ noticeably stand out for me on this system, like they're being pulled from a different font. Your font selection may be limited if you go beyond Latin Extended A, and some other people may have a harder time seeing the characters (though that could be overstated; I'm seeing them on a fairly default Windows 10 box, and up-to-date Linux and MacOS boxes should display pretty much everything but the latest additions as well.)