Top 29 Seasons in FIP ERA Since 1920

From Baseball Reference

Rank	Player (age that year)	FIP ERA	Year
1	Pedro Martinez (27)	1.395	1999
2	Dwight Gooden (19)	1.685	1984
3	Clayton Kershaw (26)	1.739	2014
4	Bob Gibson+ (32)	1.774	1968
5	Sandy Koufax+ (27)	1.852	1963
6	Sandy Koufax+ (29)	1.927	1965
7	Tom Seaver+ (26)	1.931	1971
8	Hal Newhouser+ (25)	1.966	1946
9	Matt Harvey (24)	2.005	2013
10	Steve Carlton+ (27)	2.009	1972
11	Luis Tiant (27)	2.041	1968
12	Felix Hernandez (28)	2.052	2014
13	Bob Moose (20)	2.063	1968
14	Sandy Koufax+ (30)	2.071	1966
15	Sandy Koufax+ (28)	2.076	1964
16	Randy Johnson (31)	2.081	1995
17	Sam McDowell (22)	2.081	1965
18	Don Sutton+ (23)	2.082	1968
19	Bob Veale (29)	2.107	1965
20	Bill Gullickson (22)	2.111	1981
21	Dave Righetti (22)	2.116	1981
22	Dwight Gooden (20)	2.127	1985
23	Randy Johnson (37)	2.128	2001
24	Sandy Koufax+ (26)	2.15	1962
25	Mike Scott (31)	2.157	1986
26	Don Sutton+ (26)	2.157	1971
27	Bob Feller+ (27)	2.157	1946
28	Pedro Martinez (28)	2.171	2000
29	Roger Clemens (25)	2.174	1988