I like digit 7. Doubles and 7x1
Tier 11
162(261,612,261,126,126,261,126,261,216,162)
Tier 10
910(901,109,109,109,019,910,901,109,910) 294(924,942,942,429,492,942,942,942,249)
Tier 9
803(308,380,038,830,803,308,830,083) 016(061,601,016,610,160,610,601,601)
Tier 8
207(270,720,720,072,207,702,720) 960(906,960,690,960,960,096,069) 614(614,164,416,416,416,461,641) 718(187,718,178,817,718,187,871) 278(728,827,287,278,827,287,728) 410(401,041,140,104,140,401,140)
Tier 7
073(307,307,370,370,037,703) 957(597,957,975,957,957,957) 490(094,490,940,409,094,940) 039(039,903,930,930,039,930)
Tier 6
403(034,403,043,034,034) 089(089,089,908,980,098) 172(172,127,271,172,172) 310(031,013,301,031,301) 615(516,165,156,516,561) 504(504,045,405,540,405) 529(295,952,925,529,952) 280(028,820,280,802,028) 573(537,357,735,375,357) 218(812,281,128,218,821) 274(427,472,724,724,724) 267(276,726,726,672,726) 857(857,578,857,578,587) 807(870,780,780,708,087) 547(754,547,547,745,457) 149(419,194,419,149,914) 290(029,902,209,290,290) 230(320,203,203,302,203) 891(891,819,198,819,189) 905(059,905,059,905,509) 652(526,625,652,562,625)
Tier 5
481(481,418,418,841) 851(518,158,185,815) 316(136,631,361,361) 514(451,154,451,145) 241(142,214,412,412) 532(523,253,325,523) 065(056,560,065,605) 250(250,250,520,205) 108(018,081,108,810)
Tier 4
704(740,407,407) 452(245,245,524) 305(350,350,350) 303(033,330,033) 285(852,258,582) 982(928,982,928) 192(219,291,912)) 075(570,570,705) 661(166,616,661)
Tier 3
500(500,050) 567(576,576) 900(009,090) 990(099,990) 932(923,239) 085(850,580) 015(105,501) 552(525,525) 671(176,761) 300(003,030) 084(840,048) 169(169,169)
Tier 2 275(725) 575(755) 174(471) 992(992) 707(707) 972(297) 008(080) 252(522) 880(880) 806(086) 727(772) 775(775) 571(157) 292(292)
Tier 1
170 907 722 116 414 070 550 314 411