Alex Bregman and Corey Seager are tied for the most career home runs by a player younger than 30 in the postseason, with 19 home runs.

Interpreted as:

most playoff homers before turning 30 years old by a player

	NAME	HR	G	AB	R	H	2B	3B	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Alex Bregman A. Bregman	19	97	362	63	85	17	1	54	53	9	64	3	1	426	161	37	0	2	4	10	.235	.345	.445	.790
2	Corey Seager C. Seager	19	78	299	55	76	17	1	48	42	3	79	3	0	346	152	37	0	2	3	6	.254	.350	.508	.858
3	Carlos Correa C. Correa	18	85	323	38	91	19	0	63	31	4	84	1	0	358	164	37	0	0	2	8	.282	.352	.508	.860
4	Jim Thome J. Thome	16	50	169	30	40	1	1	35	23	2	53	0	0	195	91	18	1	0	1	3	.237	.335	.538	.874
5	Kyle Schwarber K. Schwarber	15	52	165	31	40	2	0	27	33	2	48	5	0	202	87	17	0	2	3	2	.242	.371	.527	.899
6	Mickey Mantle M. Mantle	14	47	166	31	46	3	2	31	32	0	36	1	4	198	95	19	0	0	5	2	.277	.394	.572	.966
7	Jose Altuve J. Altuve	13	50	207	38	60	10	0	29	18	0	30	5	2	226	109	23	0	1	2	9	.290	.345	.527	.872
8	Albert Pujols A. Pujols	13	56	199	39	64	10	1	36	36	3	28	0	1	239	115	24	0	1	12	5	.322	.431	.578	1.009
9	Derek Jeter D. Jeter	13	99	392	69	123	16	3	33	42	5	79	13	3	447	184	32	5	3	1	5	.314	.385	.469	.854
10	Manny Ramirez M. Ramirez	13	52	188	26	42	8	0	26	28	5	50	1	0	224	89	21	0	3	3	9	.223	.335	.473	.808
11	Yordan Alvarez Y. Alvarez	12	60	214	39	63	13	3	41	31	5	69	0	0	252	118	28	0	2	5	1	.294	.393	.551	.944
12	Joc Pederson J. Pederson	12	79	195	29	50	8	0	29	17	5	61	2	0	218	94	20	1	0	4	4	.256	.332	.482	.814
13	Randy Arozarena R. Arozarena	11	33	113	23	38	5	1	17	13	2	33	3	2	128	78	17	0	0	2	2	.336	.414	.690	1.104
14	Juan Soto J. Soto	11	43	160	31	45	8	0	30	27	2	40	2	1	191	86	19	1	1	4	1	.281	.389	.538	.927
15	Aaron Judge A. Judge	11	35	135	24	31	4	0	22	23	0	51	2	1	159	68	15	0	1	0	2	.230	.340	.504	.843
16	George Springer G. Springer	11	32	130	24	40	10	0	20	17	0	37	1	0	147	83	21	0	0	1	2	.308	.388	.638	1.026
17	Carlos Beltran C. Beltran	11	22	82	31	30	4	0	19	18	1	13	8	0	101	67	15	0	0	1	1	.366	.485	.817	1.302
18	Miguel Cabrera M. Cabrera	10	41	152	23	42	9	0	30	23	2	37	2	0	178	81	19	1	0	6	5	.276	.379	.533	.911
19	Andruw Jones A. Jones	10	75	238	43	65	8	0	33	34	2	50	5	5	278	103	18	1	3	2	5	.273	.365	.433	.797
20	Chipper Jones C. Jones	10	73	261	45	81	16	0	37	57	1	48	8	3	325	127	26	1	5	10	6	.310	.429	.487	.916
21	Ryan Klesko R. Klesko	10	56	152	24	35	2	0	22	24	0	42	1	2	176	67	12	0	0	5	3	.230	.335	.441	.776
22	Kyle Tucker K. Tucker	9	72	245	32	57	8	0	29	31	0	58	7	1	278	92	17	0	2	0	4	.233	.317	.376	.692
23	Cody Bellinger C. Bellinger	9	69	242	29	51	7	3	33	25	0	87	14	1	267	91	19	0	0	3	1	.211	.285	.376	.661
24	Delmon Young D. Young	9	37	126	14	33	4	1	22	8	2	28	1	1	137	66	14	0	1	2	4	.262	.314	.524	.838
25	Evan Longoria E. Longoria	9	30	115	16	22	5	0	21	11	0	38	1	0	126	54	14	0	0	0	4	.191	.262	.470	.731