Hyeseong Kim has the best career on-base percentage with 27+ at-bats, with an on-base percentage of .485.

Interpreted as:

best obp by a player ever minimum 27 ab

	NAME	OBP	AB	G	R	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	SLG	OPS	WRC	WRAA	WOBA	WRC+	BRAA
1	Hyeseong Kim H. Kim	.485	31	14	9	14	1	0	1	5	2	0	5	3	0	33	18	2	0	0	0	0	.452	.581	1.065	8	4	.468	203	4
2	Ted Williams T. Williams	.482	7,706	2,292	1,798	2,654	525	71	521	1,839	2,021	39	709	24	4	9,791	4,884	1,117	5	20	86	197	.344	.634	1.116	2349	1,219.7	.493	188	1,067
3	Babe Ruth B. Ruth	.474	8,399	2,503	2,174	2,873	506	136	714	2,214	2,062	43	1,330	123		10,617	5,793	1,356	113				.342	.690	1.164	2727	1,436.8	.513	197	1,369.6
4	John McGraw J. McGraw	.466	3,924	1,100	1,024	1,309	121	70	13	462	836	134	155	436		4,940	1,609	204	46				.334	.410	.876	1083	354	.433	141	309
5	Herb Goodall H. Goodall	.458	45	19	10	19	2	0	0	5	1	2		0		48	21	2					.422	.467	.925	12	4.5	.450	166	4.8
6	Billy Hamilton B. Hamilton	.455	6,283	1,594	1,697	2,164	242	95	40	742	1,189	89	271	914		7,608	2,716	377	47				.344	.432	.888	1716	578.6	.433	142	505.5
7	Glenn Williams G. Williams	.452	40	13	3	17	1	0	0	3	2	0	7	1	2	43	18	1	1	0	0	0	.425	.450	.902	8	2.7	.402	151	2.7
8	Suds Sutherland S. Sutherland	.448	27	17	4	11	1	0	0	7	1	1	4	0	0	29	12	1	0				.407	.444	.893	5	1.7	.420	134	1.3
9	Lou Gehrig L. Gehrig	.447	8,001	2,164	1,888	2,721	534	163	493	1,995	1,508	45	790	102		9,660	5,060	1,190	106			2	.340	.632	1.080	2265	1,046.8	.477	173	980
10	Barry Bonds B. Bonds	.444	9,847	2,986	2,227	2,935	601	77	762	1,996	2,558	106	1,539	514	141	12,606	5,976	1,440	4	91	688	165	.298	.607	1.051	2663	1,143.3	.435	172	1,142
11	Tommy Watkins T. Watkins	.438	28	9	2	10	0	0	0	0	4	0	4	1	0	32	10	0	0	0	0	1	.357	.357	.795	5	1	.369	126	1
12	Bill Joyce B. Joyce	.435	3,310	906	822	971	153	106	70	609	721	108	303	266		4,163	1,546	329	24				.293	.467	.902	933	302.4	.430	139	267.6
13	Rogers Hornsby R. Hornsby	.434	8,173	2,259	1,579	2,930	541	169	301	1,584	1,038	48	679	135		9,475	4,712	1,011	216				.358	.577	1.010	2018	899	.459	173	863.2
14	William Gallagher W. Gallagher	.433	49	14	9	15	2	0	0	6	10	1	0	0		61	17	2	1				.306	.347	.780	12	2.2	.396	120	1.9
15	Ty Cobb T. Cobb	.433	11,434	3,034	2,244	4,189	724	295	117	1,933	1,249	94	681	897		13,068	5,854	1,136	291				.366	.512	.945	2534	1,093.6	.445	165	975.1
16	Pat Patterson P. Patterson	.432	35	23	5	14	0	0	1	5	2	0	5	0	1	37	17	1	0				.400	.486	.918	7	2.3	.425	148	2.3
17	Ollie Smith O. Smith	.432	137	39	27	41	6	1	3	20	29	3	15	13		170	58	10	1				.299	.423	.855	36	5.7	.412	117	5.5
18	Red Dorman R. Dorman	.430	77	25	12	28	6	0	0	11	9	0	6	1	0	87	34	6	1				.364	.442	.872	15	4.4	.408	132	3.6
19	Victor Rodriguez V. Rodriguez	.429	28	17	6	12	5	0	0	2	0	0	3	0	0	28	17	5	0	0	0	0	.429	.607	1.036	6	3.1	.460	190	2.9
20	Jimmie Foxx J. Foxx	.428	8,134	2,317	1,751	2,646	458	125	534	1,922	1,452	13	1,311	87		9,670	4,956	1,117	71			69	.325	.609	1.038	2135	934.1	.460	158	780.8
21	Tristram Speaker T. Speaker	.428	10,195	2,789	1,882	3,514	792	222	117	1,531	1,381	103	394	436		11,988	5,101	1,131	309				.345	.500	.928	2264	921	.436	157	812.3
22	Eddie Collins E. Collins	.424	9,949	2,826	1,821	3,315	438	187	47	1,300	1,499	77	468	741		12,037	4,268	672	512				.333	.429	.853	2032	693.4	.409	144	619.7
23	Joe Kirrene J. Kirrene	.424	27	10	4	8	1	0	0	4	5	1	3	1	0	33	9	1	0	0		1	.296	.333	.758	5	0.8	.368	121	0.7
24	John Russell J. Russell	.424	30	20	1	11	2	0	0	2	3	0	8	0		34	13	2	1				.367	.433	.858	6	1.6	.402	127	1.3
25	Ferris Fain F. Fain	.424	3,930	1,151	595	1,139	213	30	48	570	904	18	261	46	12	4,904	1,556	291	44	8	3	117	.290	.396	.820	777	203	.390	127	161