There are many Tonkatsu restaurants in Tokyo. But maybe it's easy for toulists from overseas to find it because they have a lot of branch stores. In add ition chain Tonkatsu restaurants serve stable quality of Tonkatsu.
WAKO
WAKO has a lot of branch stores in Tokyo and all over Japan. They serve Hirekatsu Teishoku Rosu Katsu Teishoku Ebi Furai(breaded shrimp cutlet) Teishoku Katsudon(かつ丼 meaning a bowl of rice topped with Tonkatsu scrambled eggs sliced onion, soy sauce and a little sweet flavor) and set meals with mixed cutlets.
The link of the website is shown below.
KATSUYA
The first KATSUYA restaurant opened in 1998 and there a re a lot of branch restaurants in Japan. The feature of KATSUYA is they serve various kinds of dishes like Hirekatsu Teishoku Rosu Katsu Teishoku Ebi Furai Teishoku Menchi Katsu(minced meat cutlet) Chicken katsu(chicken cutlet) Teishoku Katsu curry(curry topped with Tonkatsu) Katsudon and set meals with mixed cutlets.
The price is generally a little cheaper than other Tonkatsu restaurants.
The link of the website is shown below.