the Citybuilders are the most popular. Just an example:
Code:
Server Clients Companies Version
1: -BTPro.nl- #12 - CITYBUILDER - 8000pop|TEMPERATE|1980-GOAL|NOBRK|NOAIR 6 / 25 5 / 15 1.7.1
2: -BTPro.nl- #28 - CITYBUILDER APHID's - 7500pop|DESERT|1990-GOAL 4 / 25 5 / 15 1.7.1
3: -BTPro.nl- #K1 - EXTREME GOAL - 15BIL|TEMPERATE|2020-GOAL|NOBRK 3 / 35 10 / 15 1.7.1
4: -BTPro.nl- #15 - CITYBUILDER with AIR - 25,000pop|TEMPERATE|2000-GOAL|NOBRK 2 / 25 3 / 15 1.7.1
5: -BTPro.nl- #7 - HARD GOAL - 25MIL|TEMPERATE|1935-GOAL|NOSHPS|25AIR 2 / 18 3 / 15 1.7.1
6: -BTPro.nl- #2 - LONG GOAL - 1000MIL|TEMPERATE|1975-GOAL|75SHPS|100AIR 2 / 18 2 / 15 1.7.1
7: -BTPro.nl- #K3 - ULTRA HARD GOAL - 50MIL|TEMPERATE|1970-GOAL 2 / 32 2 / 15 1.7.1
8: -BTPro.nl- #4 - SHORT GOAL - 150MIL|DESERT|1985-GOAL|10SHPS|NOAIR 1 / 18 2 / 15 1.7.1
9: -BTPro.nl- #1 - SHORT GOAL - 150MIL|TEMPERATE|1990-GOAL|50SHPS|NOAIR 1 / 18 1 / 15 1.7.1
10: -BTPro.nl- #13 - MINI CITYBUILDER - 4000pop|TEMPERATE|1980-GOAL|NOBRK|NOAIR 1 / 25 1 / 15 1.7.1
11: -BTPro.nl- #31 - CARGO Goal - 300.000 units |RANDOM map|START-GOAL 1 / 25 1 / 15 1.7.1
12: -BTPro.nl- #9 - FIRS GOAL - 1000MIL|Rand.Climate|2000-GOAL|75SHPS|50AIR 1 / 18 0 / 15 1.7.1
13: -BTPro.nl- #30 - FIRS APHID's CITYBUILDER - 14000pop|TEMPERATE|1990-GOAL 1 / 25 0 / 15 1.7.1
OpenTTD doesn't have a player base that big to increase number of servers like there's no tomorrow AND dedicated servers aren't cheap. Therefore, we try to have a large variety of servers and goals, with the amount of servers we consider reasonable by their popularity.
Just imagine that other people that gets in a game already at middle of the goal and would post here for a couple more servers!
If it's your case, you have 3 options when a game is mid goal: Start company and try your best; wait till goal is reached; join another game/server.