This page only shows the main relationships in the Anime.
Aquarius
She is very moody and is easily irritated by Lucy. Whenever she gets the chance she makes fun of Lucy saying she will never get a boyfriend like she does. Aquarius' boyfriend is Scorpio, she shows a completely different side of herself to him than to Lucy. She often tells Lucy that she will kill her if she drops her key one more time in the anime it shows that she whipped Lucy as punishment for dropping her key. But nevertheless she cares for Lucy and protects her.To sum it up Lucy and her are not friends, but friendemies.
Loke/ Leo the lion
Loke is a very flirtatious person, being top ranked as the "Mage you want to have as your boyfriend", according to the Weekly Sorcerer magazines. Early during his time in Fairy Tail, a troupe of girlfriends was consistently around him, also whenever he was near Lucy he ran away. Till she saved him from vanishing and he became her spirit. Ever since then whenever Loki sees Lucy he goes in to all out flirtatious mode telling her that " because of our love I'm stronger than before". To sum it up Loke thinks of Lucy as a girlfriend thus they are under the Fairy Tail Couples list.
Plue
When Lucy first contracted Plue, he only agreed to be summoned on Tuesdays until Thursdays (in the manga)/ Sundays (in the series English dub). As the series progressed, however, it was shown that Plue is available anytime and that Lucy doesn't seem to summon him and yet he appears. Because he is not designed for combat, he serves as a cute pet for Lucy instead. He cannot speak besides saying "puu-puun", although Natsu seems to be able to understand this. He mostly communicates by using gestures and motions which Lucy finds adorable. Plue is close friends with Happy always hanging out on missions. Happy and Plue often tease Lucy and Loke. So Plue is basically Lucy's pet.
Gemini
When Gemini first met Lucy they transformed into her and controlled her spirits using her own magic. After several attempts to defeat Angel ,Lucy almost runs out of magic and Gemini reads her memories. While doing this Gemini sees how Lucy loves all her spirits and decides not to attack her. Later when Lucy goes to destroy the lacarmia without any magic Gemini shows up and helps destroy it. Gemini and Lucy like doing things together while Gemini is transformed into her. To sum it up Lucy and Gemini are like twins to each other.