One common theme is the clash of their moral compasses. Bobby is a hunter with a sense of right and wrong, while Crowley is a demon. Their interactions often involve this conflict. For example, in many fanfics, Bobby tries to use Crowley's power for good, but Crowley has his own self - serving motives.
I also like 'Crowley and Bobby: A Different Perspective'. This fanfic explores their relationship from a different angle. It delves into their past encounters and how those have shaped their current dynamic. It shows that there's more to their relationship than just animosity, with some really well - written emotional moments.
Another interesting one could be 'A New Understanding'. This fanfic could be about how they both learn from each other. Maybe Crowley teaches Bobby some demon lore that he didn't know, and Bobby in turn shows Crowley the value of loyalty among humans. It could involve a plot where they are both trying to save a small town from a new supernatural threat.
Fanfiction.net is also a place to check. It has been around for a long time and has a vast number of fanfics. However, the tagging system might not be as refined as AO3, so you may need to do a bit more digging. But it's still a good source for Crowley x Bobby fanfic.
Fanfiction.net is also a good place to look. There are many Supernatural - related fanfics on this site, and with a simple search for 'bobby x crowley', you might discover some great stories. However, the site's layout can be a bit old - fashioned compared to AO3.
There's 'Bobby and Crowley: An Unforeseen Alliance'. This fanfic is quite engaging as it starts with their mutual distrust but then slowly builds a connection between them. Also, 'The Surprising Friendship of Bobby and Crowley' is good. It focuses on how they, despite their differences, find common ground. A third option is 'Bobby x Crowley: A New Perspective' which gives a fresh take on their relationship, adding new elements to their characters and how they interact.
One popular theme is the 'enemies to lovers' trope. Given their history in the show, it's interesting to see how they could go from adversaries to having romantic feelings for each other.
Another option is Tumblr. There are many fanfiction writers who post snippets or links to their Crowley x Bobby works on there. You can follow relevant tags like #CrowleyxBobby or #SupernaturalFanfiction to discover new stories.
In fanfics, the 'weight' could refer to the significance or importance of Aziraphale and Crowley. It might be about how much they matter to the overall plot or to each other. For example, a fanfic could focus on how their relationship is the 'weight' that holds the story together during a time of great upheaval in the Good Omens universe.
I would recommend 'Aziraphale and Crowley's Adventures in London'. This fanfic is full of fun scenarios where the two characters explore different parts of London. It shows their friendship in a very light - hearted way. The descriptions of the city are also quite vivid, which adds to the overall charm of the story. It's a great starting point as it doesn't have a very complex plot and you can easily get a feel for how the two characters interact.