What's missing from the "Signs by the Numbers" page?

One goal is to have each U.S. state and Canadian province/territory
represented.  I have all 50 states.  P.E.I., Newfoundland and
Labrador, Northwest Territories, and Nunavut are missing from Canada.
I'd like to see if I can get a lot of German autobahns, because
they're a lot of fun, and other European routes, but those
opportunities are rare.

I have examples from only a small number of countries: U.S., Canada,
Denmark, Iceland, Sweden, France, Germany, Portugal, Spain, Austria,
and the United Kingdom.

I have managed to find all 99 one- and two-digit numbers (in fact, all
that can be represented in 8 bits!), but well over 100 three-digit
numbers are still missing:

284, 354, 362, 387-389, 398, 409, 426, 449, 451, 452, 454, 457, 467,
482, 483, 489, 525, 529, 553, 554, 558, 560, 569, 572, 584, 588, 591,
592, 596, 603, 625, 626, 633, 639, 645, 646, 654, 677, 692, 722, 753,
755, 761, 767, 773, 782, 783, 799, 807, 815, 816, 819, 823, 824, 830,
831, 834, 843, 844, 852-854, 857, 859-861, 867, 870-872, 875, 877,
882, 883, 891, 892, 897, 898, 905, 911, 918-921, 925-929, 935, 937,
938, 942, 943, 945, 947, 949, 950, 952, 954, 957, 958, 960-964,
966-968, 971, 974, 975, 977, 979-981, 983, 989, 993, 996, 999.

I decided not to include 4-digit numbers, even though there are a good
number of those to be found, most frequently (in my experience) in
Kentucky, Virginia, and Texas.

One goal is to have each US highway.  Missing US highway numbers:

US 73, US 195, US 730.

For a long time my only US 8 was an error shield that used to exist on
Massachusetts 8 near Dalton.  Before getting a legitimate US 43, I had
an error shield that was placed along US 7 in Williamstown,
Massachusetts, during a construction project on Massachusetts 43 in
2008.  I also have the decommissioned US 99, the nonexistent US 537
(error shield in New Mexico), the nonexistent US 132 (error shield in
Vermont), the nonexistent US 5S and US 32 (error shields in New York),
the nonexistent US 243 (error shield in Utah),
and the nonexistent US 37, US 144, US 148, US 255, and US 775 (all
error shields in Virginia) represented.

Another goal is to have each Interstate highway.  Missing Interstate
highway numbers:

I-11, I-22, I-165, I-169, I-182, I-184, I-194, I-269, I-359, I-369,
I-384, I-564, I-785.

Of these, some are represented as "future interstates": Future I-22 in
Mississippi and Alabama, and Future I-785 in North Carolina.