In the Sonic Advance series, Cream is one of the best characters to play as in boss fights, since she can fly to avoid attacks and throw Cheese at the boss without even moving, and is a good way of not getting damaged during the final boss fight.
sonic character trivia

Despite many fans having speculated that Silver is related to Shadow due to Sir Lancelot and Sir Galahad's relationship in Arthurian lore (where the latter is the son of the former), Takashi Iizuka has confirmed that Silver is not a descendant of Shadow the Hedgehog.

In Super Smash Bros. Brawl, Silver is the only hedgehog whose trophy can only be obtained once. (Shadow and Amy's trophies are obtained randomly and Sonic's trophies can be won by clearing Classic Mode multiple times).

Max also appeared in a future in which Sonic and Sally are married as King and Queen and he is a grandfather. This version of the future is where Nicole originated. He does not appear in the Light Mobius future, possibly having died at some point between the present and the possible future. In the altered timeline, however, a statue of him is in the throne room of Castle Mobius, probably in honor of his memory.

Sally was originally supposed to die during the "Endgame" saga. The idea was to kill the character with enough dignity to not drive away any of the character's fans. During a mission inside Robotroplis, Sally is slain after her rappel wire is cut, sending her falling several stories to the ground; Sonic was framed for her death. The reasoning on the part of the writers was that the arrival of King Max would displace Sally's power, making her unnecessary, and that the restrictions placed on the book by SEGA made it too difficult to continue writing the character as having a relationship with Sonic. SEGA, however, had promotional plans for the character and ordered her to be revived. Archie editor Justin Gabrie rejected the idea and made writer Ken Penders change the storyline, so that she was in a coma instead. The character's return was written into issue #50, which interfered with scheduling and caused several pages to be cut. The issue was later revised and reissued as a Sonic Super Special. Her intended death was emphasized in one of the random realities in issue #101.

Possessed of a strong moral sense near equal to his sister Sally's, Elias also has the misfortune of being born with his father's temper. This often gets him into trouble as he makes rash decisions without thinking, but he usually manages to straighten things out. Elias is also rather determined to please his father, and thus seeks any help he can get in trying to prove himself a worthy king to Max despite being told that he must rule as his own heart dictates. Doubting his ability to rule the way his people need him to, Elias is nevertheless stalwart in carrying out his duties.

Because of the ending of 30 years later (when Manik talks to Skye and how they wish each other good luck in M25YL), there is a chance that Manik and Skye may have the same kind of relationship as Sonic and Tails but different in two ways (Skye's shyness and the way that he and Manik deal with things).

Strangely, Amy appears in the French guide for Sonic & Knuckles, even though she makes no appearance whatsoever in the game. In that guide, it was said that Amy had been kidnapped by Knuckles.

Amy's last name, Rose, can be considered a play on words. A rose is a flower that is connected with love, which can be related to her crush on Sonic. It is also a play on her color, because in French, rose translates to pink, her fur color. Her first name, Amy, could also be derived from the Japanese word ame, meaning candy, related to Amy's cute personality, but also rain, which can be related to her quick changing temper and power when she's angry. It could also be derived from the French name Aimée which means beloved which also fits with her connection to love.
Tails has the most voice actors out of all of the characters, with nine English voice actors (counting his TV show and movie appearances). Often times, Tails was cast with young boy voice actors to provide a genuine youthful male voice for the role, although this would always cause the need to recast him once the voice actor's voice matured too far to continuing voicing him. In recent years, Tails has been voiced by females, in order to avoid the aforementioned issue.