Here's a list of all the 4* on JP so far.. (Mainly made this because a Twitter account that made the compilations for these was too slow so I took the matters into my own hands.)

Other random statistics
X amount of event since last 4 star

• 0: KF Kasumi & Yukina, Lock & Nanami; Bday girls Sayohina
• 1: Misaki, Rinko & Arisa; DF Aya & Himari
• 2: Rui & Masking
• 3: Eve & Maya; Bday girl Mashiro
• 4: Touko & Tsuku
• 5: KF Pareo & Kanon, Tsugu
• 6: Kaoru; Bday girl Layer
• 7: Hagu
• 8: DF Lisa, Chisato
• 9: Chu2
• 10: Tomoe
• 11: Ako; Bday girl Tae
• 12: Moca & Ran
• 13: Rimi
• 15: Kokoro
• 21: Saaya

X amount of Limited 4 stars (including dreamfes, kirafes & birthday cards)

• 9: Arisa, Hina, Kasumi, Kokoro
• 8: Aya, Lisa, Sayo, Yukina
• 7: Chisato, Kanon, Moca, Ran, Tsugu
• 6: Eve, Himari, Rimi, Saaya, Tae
• 5: Ako, Maya, Misaki, Rinko, Tomoe
• 4: Hagumi, Lock
• 3: Chu2, Kaoru, Mashiro, Nanami, Pareo
• 2: Masking, Nanami, Tsuku
• 1: Layer, Rui, Touko