Colorful

Golden Boy can be considered as Colorful with a plot and much more variety in humor. Sure, it's still ecchi but there's also a lot more to it than just that. 

Both are 6 minutes long with a total length of 16 epsiodes, Both focus on Comedy and Ecchi very heavily, In my opinion more so in Iketeru Futari, they also have an extra genre, In Colorful it's School, in Iketeru Futari it's Romance. Both have quite large casts, although the episodes in Colorful have segments, Iketeru Futari usually revolves around the 2 main characters. 

This show reminds me a lot of Colorful, because of the randomness of the plot and the ecchiness ofthe humor. Also, it aired around the same time as Colorful. Makes me wanna go back and rewatch Colorful again. But Nupu Nupu is more WTF than Colorful . so i'd say Nupu Nupu is funnier. 

There is a lot to differentiate Pop Team Epic from Colorful, but at their core each show has the same comedic essence. Explicated better, both these shows are skit comedies that rely on drawing in viewers with their variety of lightning-fast comedic moments. Both shows feel like the kind of hectic Internet humour often found in YouTube videos. 

"The Bride Stripped Bare by Her Bachelors" and "Colorful" are works with the focus on the topic of sex, in which they both incorporate uniquely styled hand-drawn animation alongside photographs of real-life. 

Really different plots, but the exact same structure, with short stories about different people always following the same theme. Each episode has a few segments, some of them self-contained, and some which tell longer narrative with characters that recur throughout the episodes. Eventually, some of the characters also meet. 

For both of these shorts series, the focus is on random situations with comedy and ecchi playing large roles. 

Short fetish type Anime, where the Male characters want to do nothing more than glimpse women's panties. 

These 2 fetish type Anime center around certain Female clothing items- Tights in Miru Tights (obviously!) and Panties in Colorful. Both are Ecchi throughout. 

Short fetish style Anime, where the Male characters want nothing more than to glimpse women's panties. 

Short episodes involving aroused males who are ogling at female underwear in a comical way. 

Ecchii-ness , Both touches on awkward topics that makes, u cant help but just laugh. Obvs by the year difference Oretachi is a smoother on the eyes. though imo both decent animes 

Weirdness and ecchi-humor at it's best! 

It's another short series with weird humor. 

Although GTO actually has a consistent plot and story (where Colorful doesn't), they both use the same style of overly-expressive facial animations. This is a good thing IMO. 

If you enjoyed colorful then you will undoubtedly enjoy green green. 

Similar perverted/sexual spying on women 

Both animes have no plot at all and revolve purely around Penis Humor. Colorfuls focus is more on men and their misadventures when trying to take a peak, while Panty & Stocking is focusing more on spoofing other series. But still the kind of humor in both series is the same. 

Both anime are crazy, full of expression, action and vulgar jokes. Also, they have short episodes.