Free! Eternal Summer

The simmiliarty between the Redline and Free!: Eternal Summer is the main character or in the Free case characters. All of them are showing a determination to be the best there can be. 

Same sports thematics - this time it's tennis.  

While K-On! is not a sports anime, it shares a lot in common with Free! in terms of its focus on friendship and the bonds between its characters. 

Both shows tend to focus on more about the lives of the characters, with the Sport aspect being used to drive the plot. They both also contain well-done drama about the pasts of some of the important characters. Both shows as well have various moments of yaoi-bait depending on how one interprets them  

if you liked the first season, the second one only gets better as the characters are forced to break out of the highschool anime bubble universe and confronted with the reality of graduation. just don't expect it to be a "sports anime" the same way haikyuu or knb are. free is just a coming of age drama about guys who happen to do sports and it only gets more melodramatic from here on out :) 

Both are yaoi, full of attractive pretty boys and based on sport. Yuri!!! is a lot more of a focus on butts and ice skating (obviously considering the title) where as Free! is based on a boys high school swim team and the friendships that stemmed from that. Both are lighthearted, pretty, fun and... russian men and shirtless guys, what more could you ask for? 

If you like anime about basketball than you'll defenetelly like Kuroko no Basket. It's one of the highest scoring anime shows about sport and has an enormous army of fans all around the world. 

If you love having boyxboy ships, these both anime are the way to go! Both have really close bromance relationships, up to the point when you're thinking "just kiss already!" Free! is about swimming and Binan is about defeating everything with the power of love! but both share the similarity of five guys loving their dude friends.  

Despite the content being inherently different (sports vs. music), the themes are actually quite similar. Competition, pressure to be perfect (especially in front of an audience), relationships between friends, and more are all common themes. Relating to one show means you will likely relate to the other. 

Well, that's my first time making a recommendation, I hope this will help you ^^" : - Both are about an all boys sport club with a female manager/coach. - The character development! you can clearly see the difference between the 1st and 2nd season in both anime's! - Both are sport, comedy, slice of life genre with some drama. - Seiyuu's! Both have great seiyuu's! and you totally can enjoy the voice acting X') - Both have great art style and good graphics. - Both have great opening and ending songs. - Both are mistaken for being yaoi (gay....) while it's just a friendship show with a lot of bromance X''D ... But it's Not a yaoi ^^" read more 

Both shows theme are passion, dreams, and future. Both shows' protagonists initially doesn't have dreams like the other characters who surrounds them. There are "cool, talented, but airhead" main characters (Haru and Mashiro) in both shows and getting care as well as envies (for Free!, it's in 1st season) from other characters. Both shows also have comfy, funny, as well as melancholic moments. There are some fanservices (Sakurasou's is mainly aimed to guys, and Free: Eternal Summer to girls) in these shows, but not too much so you can easily ignore them (the fanservices), took off the fanservice/shipping-glasses if it's not your taste, and you can still enjoy the shows. read more 

The main characters of both anime have conflicts with their best friend in the last days of their high schools. Both main characters are playing sports - swimming in Free! ES, basketball in Hana. While one has supernatural element and the other doesn't, both have some emotional moments. Both have some characters who might have been permanently injured. 

Like Free!: Eternal Summer it's centered around a school club. While in Free! it's swimming, in Hyouka it's solving mysteries. The most similar element between Free! and Hyouka are the similarities between Haru and Houtarou. They essential have the same situation, a very talented boy with tons of potential and little motivation. While Haru gains his motivation from racing his friends, Houtarou finds his in a, somewhat Gou-like, girl who is curious about everything. Both animes are pretty light but reach dramatic points in the later episodes. Both are pretty funny. The art style is also pretty similar. If you liked Free! Or were amused by Haru's character in general, check out Hyouka. read more 

Group of guys doing weird shit. The Ending song/video makes me think strongly of Meganebu!