Tom Seaver is in Mets top 8 pitching seasons three times.

For Single Seasons, Playing for the NYM, From 1871 to 2018, (requiring ERA+>=160 and Qualified for league ERA title), sorted by greatest Adjusted ERA+

Rk	Player	ERA+	Year	Age	Tm	Lg	G	GS	CG	SHO	GF	W	L	W-L%	SV	IP	H	R	ER	BB	SO	ERA	FIP	K%	BB%	BAbip	HR	BF	AB	2B	3B	IBB	HBP	SH	SF	GDP	SB	CS	PO	BK	WP	BA	OBP	SLG	OPS	OPS+	Pit	Str
1	Dwight Gooden	229	1985	20	NYM	NL	35	35	16	8	0	24	4	.857	0	276.2	198	51	47	69	268	1.53	2.13	25.2%	6.5%	.262	13	1065	986	23	3	4	2	6	2	21	22	10	5	2	6	.201	.254	.270	.524	52
2	Jacob deGrom	216	2018	30	NYM	NL	32	32	1	0	0	10	9	.526	0	217.0	152	48	41	46	269	1.70	1.99	32.2%	5.5%	.283	10	835	776	27	3	3	5	3	5	13	15	8	1	0	2	.196	.244	.277	.521	52	3212	2213
3	Tom Seaver	194	1971	26	NYM	NL	36	35	21	4	1	20	10	.667	0	286.1	210	61	56	61	289	1.76	1.93	26.2%	5.5%	.267	18	1103	1021	31	4	2	4	11	6	25	7	3	3	1	5	.206	.252	.297	.549	61
4	Tom Seaver	175	1973	28	NYM	NL	36	36	18	3	0	19	10	.655	0	290.0	219	74	67	64	251	2.08	2.57	21.9%	5.6%	.247	23	1147	1064	35	5	5	4	10	5	17	5	3	0	0	5	.206	.252	.313	.565	62
5	Al Leiter	170	1998	32	NYM	NL	28	28	4	2	0	17	6	.739	0	193.0	151	55	53	71	174	2.47	3.15	22.1%	9.0%	.276	8	789	699	37	1	2	11	6	2	24	11	4	0	1	4	.216	.298	.306	.604	65
6	Johan Santana	166	2008	29	NYM	NL	34	34	3	2	0	16	7	.696	0	234.1	206	74	66	63	206	2.53	3.51	21.4%	6.5%	.278	23	964	887	36	5	5	4	9	1	12	6	5	2	2	9	.232	.286	.362	.648	75	3598	2387
7	Tom Seaver	165	1969	24	NYM	NL	36	35	18	5	1	25	7	.781	0	273.1	202	75	67	82	208	2.21	3.11	19.1%	7.5%	.238	24	1089	975	35	7	9	7	20	5	18	7	4	1	1	8	.207	.272	.331	.603	72
8	Jerry Koosman	160	1969	26	NYM	NL	32	32	16	6	0	17	9	.654	0	241.0	187	66	61	68	180	2.28	2.67	18.8%	7.1%	.256	14	957	864	29	4	11	4	16	5	25	9	5	0	2	7	.216	.275	.308	.583	67

Seaver 3rd best ERA+.