Were there ever any recurring suspects?

[mangaluva]

Eri. 

[Callid]

That...that guy! Yeah! That guy appears more than once! Everyone knows that guy!

... I'm sure we can call him a mass murderer now...

[jocelle0211]

@Olive: You were asking about why Gin and Vodka rode on the roller coaster, right? Vodka clearly stated that they rode the coaster together because they had a complete geographical overview of the park. Also, they wanted to make sure that the Company President is alone in a dark place together with the suitcase loaded with millions of yen.

[Abs.]

@Olive: You were asking about why Gin and Vodka rode on the roller coaster, right? Vodka clearly stated that they rode the coaster together because they had a complete geographical overview of the park. Also, they wanted to make sure that the Company President is alone in a dark place together with the suitcase loaded with millions of yen.

...and you're accepting his answer?  Clearly Gin and Vodka were having a romantic day together.

[mangaluva]

@Olive: You were asking about why Gin and Vodka rode on the roller coaster, right? Vodka clearly stated that they rode the coaster together because they had a complete geographical overview of the park. Also, they wanted to make sure that the Company President is alone in a dark place together with the suitcase loaded with millions of yen.

but isn't it stupid to blackmail someone in a crowded park in the first place?

Well, they were ensuring that he was in a secluded place in the park alone, and it would probably be stupider to require the park owner to leave the park with a dubious alibi to where he was going.
Plus, they can get candyfloss on their way out.

[jocelle0211]

They were checking on the Company President AND were having a romantic date together. Vodka told him that excuse because he doesn't want anyone to find out that they're dating each other. ALIBI, for short. Q(^.^)Q

[Chekhov MacGuffin]

Totally missed this topic since I was out, but I made a list of recurring minor characters somewhere else before. I forgot where so I will repost the latest version...

Later Edit: This is outdated. Please refer to here for the most recent version.

Azusa Enemoto, waitress at Poirot, the coffee shop below Mouri detective agency. The boss of the café loves deductions, so he named the shop after the detective (440). She shows up in 276 (Heiji’s Mom), 407 (offered to baby sit Conan while he is sick), 438-440 (cell phone case), 523 (fish streamer case), 553, 569, 594, 641-642 (Azusa’s brother murder case), 674 (Iron Tanuki)
The sign appears only in 2, 6, 14, 49, 162, 234, 276.09?, 395.16 (red horse arson). Note the sign says coffee and ポアロ
Sugihito Enemoto is Azusa’s brother who does clay shooting. (Clay shooting shows up in 243. I wonder if it is the same group? No names match though.) One blond Hiroshi Enomoto shows up in 437 (the three car case). The relationship if any is unknown

Kaneshiro Genichirou, owner of a computer company, age 74, he owns islands in Okinawa and wants to increase tourism. Appears in 72 as a participant in the night baron case in Izu, 361-365 (solitary island of the princess Goosoh). He had a son who died four years ago. (a euphemism for his game?) (73.10) In the Night Baron case he pretends to be blind to throw other participants off. Apparently the virus ruined the girl game he created four years ago. In episode 291 (Goosoh case ep) a mayor by the name of Kaneshiro Hyogo (age 63) appears. He seems to be a relation to Genichirou. Kaneshiro. Miyako is the daughter of Hyogo. Genichirou has a servant named Hayashi Shizue.

Sanada Kazumi, age 27, Magician, appears in 131-133 (Magician double card case), 158 (Kaito kid on a boat), 192 name mentioned (magic club meeting), 269 Takagi has tickets to his magic show (Transporting suspect on the train case), 487 brought up in connection to the mystery house.

Sumiko Kobayashi, age 26, teacher of the detective boy's class 1B. The previous teacher was named Toya. She appears in 154 (Strange wonders of the school aka moving silhouettes case), 176, 303 (Genta’s murderous haircut) – brief appearance, 505 (The suspicious new teacher), 515 (interview of the detective boys), 548 (The mysterious 200 faced man), 689 (Sakura chain of memory)

Akagi Hide, soccer star, appears in chap 70 (younger brother kidnapping case), 189 (stadium bombing case), 344, 366, 567

Natsue Hatamoto, age 22, her family is all messed up by selfish relatives who want the inheritance: ownership of Hatamoto construction company and a lot of money. The company itself has corruption allegations and debt issues. They are rich enough to own Hatamoto Island and rent a huge boat. Natsue’s parents (father = Shouichi, mother = Miyuki) died in an accident of some sort the year previous. She renounced the inheritance to live with her husband. Suzuki Kenji = family butler unknown relationship to Suzuki family…
Natsue appears in chap 20-25 (Hatamoto murder case), 26, 215 in a letter (train case),
Hatamoto Shouji - the cook, 20-25 (Hatamoto murder case), 158 (Kaito kid on a boat.)

Osamu Kenzaki (actor who plays katana wielding TV detective Samonji) He appears in 182 (mystery writer case Climax of .5): note the proximity to Ai’s introduction, 322-324 (gathering of the idols), he appears on the cover of a book in 441

Mifune Takuya, age 26, Mifune electronics industry president, has dark skin, a black ponytail and a hairsplit down the middle of his hair. Reappearing character in 87 (face in water drowning case), 158 (Kaito kid on a boat.)

Suzuki Ayako, age 24, Graduate student interested in film. She is in a film club and is the head of makeup and costumes. She is Sonoko’s older sister who owns a villa and will be getting married to Yuzo Tomisawa, age 28, who’s father is the head of Tomisawa Zaibatsu (122). Suzuki Shirou is Sonoko’s and Ayako’s father as well as the head of Suzuki financial corp. Suzuki Tomoko is the mother.
She shows up in 40-44 (bandaged man case), mentioned in 45, 122 (triplets case), 158 (Kaito kid on a boat.)
Yuzo Tomisawa shows up in 122 (triplets case), 158 (Kaito kid on a boat.)

Ida Gan - A fisherman, 460 (poisoned bait case), 664 (Ikkaku rock case)

Okino Yoko, 6-9 (yoko’s murder case), 104 (death on live TV), 322 -324 (gathering of the idols), 591, Mentioned in 166, 401

Medical student Katsuragi Yukiko, age 24, and Tsujimura Takayoshi, age 27 is studying justice. They are half siblings. Katsuragi Yukiko is the daughter of Tsujimura Kimie’s first husband Yamashiro Kenji, a diplomat. Tsujimura Takayoshi is the son of Tsujimura Isao, a diplomat who landed Yamashiro Kenji in jail by framing him in a corruption scandal. 92-95 (No immunity for the diplomat) - do note that Conan turned back into Shinichi during this case, 283 (And there are no mermaids) – Katsuragi grew up on the island and recommended Kudo to her old friend Saori who wrote the letter to Hattori requesting Kudo’s help (the I’m going to be killed by a mermaid letter). Note they don’t appear in the anime version of the mermaid case.

Dr. Tomoaki Araide (the real one), 234 – 237 (Dr Araide’s murder case), 457-459 (Teitan high’s ghost story), 507 (The suspicious new teacher) [Hikaru also shows up in this one]

Shinichi’s high school friends:
Nakamichi (male soccer player) – 457 (Teitan high’s ghost story), 597 (Red vs. black) helped hide Eisuke at the hospital
Aizawa (male soccer player) 457 (Teitan high’s ghost story)
Tashiro (talkative female) 457 (Teitan high’s ghost story)
Hidaka (talkative female) 457 (Teitan high’s ghost story)

Nanakawa Aya – friend of Ran and Sonoko from junior high
Convenience store shoplifting case (426-428)
In hospital where Mizunashi Rena is being held, she is recovering from appendicitis (ep 491)

Kikuemon famous potter – murdered in one case near the beginning of the manga I think, mentioned in Pottery class murder case (305 -307)

Teitan headmaster - strange wonders of school, also mentioned in 458 (teitan ghost case) has a thing for planting trees on campus in strange ways…