VOCALOID is a voice synthesizing software released in 2004 and developed by Yamaha Corporation. You make a melody and type lyrics/'speech' and it sings for you!
Vocaloid is both the name of the program, and the term used for the avatars each voicebank is released as (avatars as in the singer, like Miku)
that being said, there are a lot of other vocal synthesizers out there by different names with their own voicebanks!! sometimes they can get tossed under the name vocaloid which can be confusing lol. this page is mostly for yamaha's vocaloid software specifically, but I might mention or make other pages for UTAU and other things eventually since I love those too!

as far as I know, I was introduced to vocaloid in 2013 through Giga-P's arrangement of Electric Angel. I thought the MV was cool and I was obsessed with Len's vocals lol. after that I just listened to more over time starting with songs like Meltdown, World is Mine, Ten-Faced, etc. little did I know, this would become the first interest of mine my brain gave 100% of it's attention to and would encompass all of my music taste for YEARSS GRAHHH. I still love it so so much. I think what's so nice about it to me is the use of the same characters for tons of different genres and stories. I can find something totally new and unique, but find familiarity in the voices used, and I like things that way :) and vocaloid has just been a very big part of my life for so long now it is like a dear friend to me

HACHIIII aka Kenshi Yonezu is. MY FAVORITE MUSICIAN LOL. I've been listening to his music for a very very long time and I love all of it a lot..his improvement over time has been incredible and it makes me so happy. this is just here for me to be insane about all his work in general for a moment GGRAHHHH AAHHHHH WEEEEEEEEE
favorite songs: Panda Hero, Donut Hole, Ward Room 305, I'm not listing my favorite non vocaloid songs he's released but I have so many. I love his work. OK

I've been listening to siinamota's music since early 2015 I believe? his music to me feels very grounded yet kind of spaced out, the way going out and doing daily tasks by yourself is. I've always felt very connected to his work and hold it close to my heart. may he rest in peace
favorite songs: Help yourself to seconds, Han Shin Han Gi Me, DrugScore, Everyone's Apocalypse, Dream Inside a Dream, A Palette Full of You, From 9 to 0, In My Head

oh god I have no idea when I found kikuo's music. but whenever I did I loved it immediately LOL. to me especially in the earlier years he was like. The guy who made the really fucked up happy sounding vocaloid music. I think that's more common now, but back then I remember if anyone was joking about that kind of vocaloid music, they were absolutely talking about kikuo. and I mean..Yeah
favorite songs: The Good Child and The Fox Spirit, Missing Missing, Welcome to the Star Inn, Lie Lie Lie, First Cry, Don't Look At Me in That Way

abuseken debuted more recently than the other producers listed here..and I don't see people talk about their music much either? it's very good!!! probably obvious given their name, but they make music about a lot of very heavy topics. their work is very intense and emotionally charged, it feels very alive to me.
favorite songs: FIREWATER, Summer of Frostbite, Um Ren-kun?, snorkel, Wan Wan Wanderer, Want to be Cremated, Shinjuku Jack, iesu

music that makes me twirl my hair run and jump around BAHAHA I love slave.v-v-r's do I describe it. kinda jazz kinda rock. I kind of want to describe it as classy...I also adore his music videos!! the animation is so pleasing to my eyeballs
favorite songs: An abominably huge flower, God mistook my gender, Hit You 8759632145 Times With This Piano, Let's die together in Kurashiki, Ultra rupture, Love Eater

wowaka was one of the first vocaloid producers I really listened to a lot, it wouldn't surprise me if he was for a lot of people. his work was so powerful and so influential..his music is very dear to me. I don't have a lot of words for how I feel about it? it has a very particular sound. like when your brain is loud. I love it. may wowaka rest in peace
favorite songs: Grey Zone ni te, Toosenbo, Two-Faced Lovers, Rolling Girl, Unhappy Refrain, Unknown Mother Goose

favorite songs: TBA

favorite songs: TBA

favorite songs: TBA

favorite songs: TBA

KAITO is my favorite voicebank by far and truly I think the moment he became my favorite was when I played Snowman on Project Mirai DX in middle school. I absolutely adore that song and his voice.. I know a lot of people say he sounds kind of weird sometimes (a little like kermit. SIGH) but when he's tuned well UMMMM his voice is VERY pretty, I think. I just love hearing it idk it makes me smile it makes me happy. and overall I just think he's cute, honestly. I can't claim to be number 1 KAITO fan though because his voice provider Naoto Fuuga holds that title forever.
Favorite Modules: Diamond Dust, Requiem, Cyber Cat

I also love Rin and Len a lot, they are dear to me :) they were the first vocaloids I ever heard and were my absolute favorites for a really long time. and I'm a twin and they used to remind me of my brother and I lolll
Favorite Rin Modules: Astray, Asymmetric R, Raspberry Fox, Heat Haze
Favorite Len Modules: Receiver, Eraser, Ice Fog, Indigo Fox

OTHER VOICEBANKS I REALLY LIKE INCLUDE: MEIKO, Gakupo, GUMI, VY2, Nekomura Iroha, Hiyama Kiyoteru, Utatane Piko