Season 1
CASUAL CLOTHING 
These are the clothes Tai wears almost all the time in the first season. When we first met Tai, we saw this blue shirt with orange stars on the sleeves, yellow collar and white gloves. He also has this black wristlet on his left hand. His trousers are brown with big pockets, where he keeps his telescope. He wears white socks (almost under his knee, which we probably wouldn't do in the real life xD) and sneekers.
We musn't forget about his famous goggles. He takes them off when he sleeps (not in digiworld) or takes a shower. Under the goggles is a blue band, he continues to wear in the second season. He gives his goggles to Davis.
I hope this isn't considered as hentai ^^' (I blured his bottom xD). We saw Tai's bottom in one of the first episodes (season 1). Digidestined took a bath and so they were all, naturally, naked. Tai's skin is much more darker than, for example, Matt's or Joe's.
ALMOST NAKED
When devimon orders leomon to attack the digidestined they were all sleeping (or going to the toilet like Tai xD) in their frocks (I found this word in the dictionary, I hope it is the right one!). When leomon attacked Tai, the boy lost his frock and he was only wearing his underpants. He has blue underpants (and he doesn't change them through the show o.o).
In the episode when Mimi gets her crest and they spend a day on a fancy ship, the boys lay in the sun without their shirts on.
TRACK SUIT
Since Tai plays soccer in a soccer team, he wears their track suit. It is red with white stripes, collar and number on the backside (I must check which one Tai wears). It is interesting that he doesn't wear goggles while playing soccer.
LITTLE TAI
Tai made a special trip with agumon in a hole, where he met himself as a child. The little Tai was trying to cycle on a bridge but he wasn't very successful. Tai helped him ride a bike and he dissapeared. It was a very strange episode o.o. However, Tai was wearing a blue shirt and maybe jeans. His goggles were hanging around his neck.
The second little Tai was seen in episode 48, when Tai was explaining Izzy how he wanted to play with Kari even though she was ill and how she fainted because she had a really high fever. I don't know what colours his clothes are because the memory was black and white. He was wearing a t-shirt with a typical star on it and short trousers.
Season 02
SCHOOL UNIFORM 
In the second season Tai is already visting high school. There is this tradition in Japan that every high school has its own uniform. Tai's uniform is a white shirt with collar, a green jacket and gray trousers. In the beginning, he still wears his goggles. When he gives them to Davis he sometimes wears his blue band but his hair doesn't need any support to stay in the air anymore (maybe he's using a speacial gel or something xD).
CASUAL CLOTHING
This could be Tai's casual clothing in season two. Blue T-shirt with triangles on the sleeves and chest (that replaced the stars!), under this T-shirt another one, a green one, gray trousers and yellow wristlets. This is my favourite one! <3
Well, it's just what he's wearing at home and among his friends. It's dark blue and there is a yellow paw on in. I always thought it was agumon's paw. xD
The jacket is probably a part of his training suit. It's also blue (not that dark blue) and has a yellow paw in the front. It also has cowl and that's what Tai's wearing in the winter so it must be quite warm underneath!
BUSINESS SUIT
When Tai grows up, he is a lawyer. It's a must to have a business suit if you're something more important and his is dark blue. His shirt is white and his tie light blue. He also has a black suitcase. What's not a clothing but it is something very important is his hair! He cut his hair! O.o
When digidestined organise their reunion (with all their children and digimon), we see Tai's light blue (or green, not sure xD) jacket, yellow shirt underneath and blue trousers. But that's all what we see of him, he's there as though he was just an unimportant character! He could at least say a word or two more ... (and so could everybody else!). :o
Movies
LITTLE TAI IN THE FIRST MOVIE 
First he's wearing his pajamas. The colour is very light purple and he's already wearing his goggles (around his neck)!
Blue shirt with long sleeves and (again) a star on them. Funny long trousers, gray and poor green. His hair doesn't need any support to stay up. He wears the same outfit in the fourth movie where he's only seen on a picture and has only two teeth. xD
TAI IN MOVIE 2
In the second movie Tai wears his casual clothing. The difference is only that he has a dark blue shirt with long sleeves underneath it. He also doesn't wear his gloves. Much cuter in my opinion!
TAI IN MOVIE 3
In the beginning of the movie Tai wears a green T-shirt, very similar to his casual shirt in the second season. His trousers are brown and he's playing with a ball. Then he dissapears and finds himself in chocomon's world. Later his clothes change and he's wearing his usual clothes from the first season, he's getting younger.
The younger he gets, the more do his clothes change. We see the little Tai, wearing a blue T-shirt with a star on his chest (what a surprise! A star!). This shirt is the same as the one in episode 48 (season 1), when he remembers the day Kari fainted because of him
TAI IN MOVIE 4
Blue short-sleeved shirt with collar with a STAR on it ... C'mon, Tai, you can already wear something else ... -.- (joke) His shirt is really long and underneath it is also a dark blue shirt. His trousers are very dark, blue or black, and very tight. He looks much older in this outfit, doesn't he? :D
