how many players have recorded 20 rebounds in a single game before turning 21

Donovan Clingan got 20 rebounds against the Nuggets on February 12.

Interpreted as:

How many players have recorded 20 or more rebounds in a single regular-season game before turning 21 years old?

	NAME	DATE	REB	AGE	TM		OPP	MIN	PTS	AST	STL	BLK	FGM	FGA	FG%	3PM	3PA	3P%	FTM	FTA	FT%	TS%	OREB	DREB	TOV	PF	+/-
1	Donovan Clingan D. Clingan	2/12/2025	20	20-355	POR	@	DEN	31	17	2	0	3	7	12	58.3	0	0		3	5	60.0	59.9	10	10	1	5	-10
2	Victor Wembanyama V. Wembanyama	10/28/2024	20	20-298	SAS	vs	HOU	35	14	5	0	4	6	14	42.9	1	5	20.0	1	2	50.0	47.0	5	15	4	3	-7
3	Victor Wembanyama V. Wembanyama	3/29/2024	20	20-085	SAS	vs	NYK	38	40	7	2	1	13	22	59.1	4	9	44.4	10	12	83.3	73.3	5	15	4	2	+1
4	Jalen Duren J. Duren	3/13/2024	23	20-116	DET	vs	TOR	28	24	5	1	0	8	9	88.9	0	0		8	10	80.0	89.6	9	14	5	3	+9
5	Jalen Duren J. Duren	2/8/2024	22	20-082	DET	@	POR	37	27	1	0	3	9	15	60.0	0	1	0.0	9	10	90.0	69.6	8	14	3	5	+4
6	Jalen Duren J. Duren	1/28/2024	21	20-071	DET	vs	OKC	31	22	6	0	1	9	13	69.2	0	0		4	5	80.0	72.4	9	12	1	2	+1
7	Victor Wembanyama V. Wembanyama	12/8/2023	20	19-338	SAS	vs	CHI	32	21	4	1	4	8	20	40.0	0	4	0.0	5	6	83.3	46.4	7	13	1	2	-22
8	Alperen Şengün A. Şengün	4/7/2023	21	20-256	HOU	@	CHA	32	14	3	2	1	4	9	44.4	1	1	100.0	5	6	83.3	60.1	5	16	4	4	+5
9	Isaiah Stewart I. Stewart	4/16/2021	21	19-329	DET	vs	OKC	32	15	3	0	2	7	12	58.3	0	1	0.0	1	2	50.0	58.2	9	12	1	4	+20
10	Mitchell Robinson M. Robinson	3/28/2019	21	20-361	NYK	vs	TOR	31	19	0	1	2	8	12	66.7	0	0		3	6	50.0	64.9	9	12	0	3	-10
11	Jarrett Allen J. Allen	1/16/2019	24	20-270	BKN	@	HOU	43	20	2	0	3	10	19	52.6	0	3	0.0	0	1	0.0	51.4	6	18	0	3	+14
12	Karl-Anthony Towns K. Towns	4/3/2016	21	20-140	MIN	vs	DAL	44	11	9	1	3	5	13	38.5	0	3	0.0	1	1	100.0	40.9	3	18	6	3	-4
13	Andre Drummond A. Drummond	4/11/2014	26	20-244	DET	@	CHI	42	26	0	3	1	11	17	64.7	0	0		4	9	44.4	62.0	12	14	2	4	+1
14	Andre Drummond A. Drummond	4/5/2014	20	20-238	DET	vs	BOS	40	19	0	0	1	9	11	81.8	0	0		1	2	50.0	80.0	7	13	2	2	+11
15	Andre Drummond A. Drummond	3/9/2014	22	20-211	DET	@	BOS	38	18	0	1	0	8	13	61.5	0	0		2	3	66.7	62.8	10	12	2	2	-9
16	Andre Drummond A. Drummond	3/3/2014	26	20-205	DET	vs	NYK	46	17	0	2	3	6	9	66.7	0	0		5	7	71.4	70.4	7	19	0	2	+13
17	Andre Drummond A. Drummond	2/18/2014	22	20-192	DET	vs	CHA	34	16	1	1	2	8	15	53.3	0	0		0	2	0.0	50.4	11	11	1	5	-9
18	Andre Drummond A. Drummond	2/7/2014	22	20-181	DET	vs	BKN	40	16	1	1	1	7	12	58.3	0	0		2	8	25.0	51.5	8	14	3	4	+12
19	Andre Drummond A. Drummond	1/24/2014	20	20-167	DET	vs	NOP	39	21	1	1	2	9	17	52.9	0	0		3	6	50.0	53.5	10	10	2	4	+11
20	Enes Kanter Freedom E. Kanter Freedom	3/1/2013	22	20-285	UTA	vs	CHA	44	23	1	0	1	10	12	83.3	0	0		3	4	75.0	83.6	5	17	5	1	+26
21	DeJuan Blair D. Blair	4/14/2010	23	20-357	SAS	@	DAL	37	27	4	3	0	12	21	57.1	0	0		3	4	75.0	59.3	8	15	3	3	+9
22	DeJuan Blair D. Blair	1/13/2010	21	20-266	SAS	@	OKC	31	28	0	2	2	11	17	64.7	0	0		6	8	75.0	68.2	10	11	2	6	+7
23	DeAndre Jordan D. Jordan	1/25/2009	20	20-188	LAC	@	GSW	41	8	1	0	1	3	8	37.5	0	0		2	7	28.6	36.1	7	13	1	3	-9
24	Dwight Howard D. Howard	11/20/2006	23	20-347	ORL	@	MEM	41	24	1	1	1	9	12	75.0	0	0		6	8	75.0	77.3	8	15	3	0	-3
25	Dwight Howard D. Howard	11/18/2006	21	20-345	ORL	vs	CHA	30	24	2	1	0	7	12	58.3	0	0		10	13	76.9	67.7	6	15	1	2	+6