Each tech will have at least a unit or wonder or building or worker action associated with it - there will be none that are there simply as a bridge to other techs. Some of these are already in the mod as you can see.
Scaffolding is a trait-specific advance which follows Masonry. It is associated with the Seafaring civs and leads to the Great Lighthouse (so only seafaring civs can build that wonder). The other options are as follows:
Agricultural civs: Epic works - leads to Pyramids.
Commerical civs: Commerce - leads to Colossus.
Expansionist civs: Mortar - leads to Mausoleum of Mausollos.
Industrious civs: Fortification - leads to Great Wall.
Militaristic civs: Terracotta - leads to Terracotta Army.
Religious civs: Marble Working - leads to Oracle.
Scientific civs: Bricklaying - leads to Great Library.
All of the wonders above have the same effect as in the epic game, with the exception of the Mausoleum of Mausollos. This gives a free burial mound in each city (the burial mound just adds 1 culture per turn). The terracotta army allows a free barracks in every city. Essentially, the Oracle has the same effect - it's just that there's no temple in the first era, there's a shrine instead, but it does exactly the same as a temple.
*Please note that whilst all civs have two traits, one of the traits is what I call a "primary trait" - it is that trait which decides which advance will become available. For example, the Illyrians are Seafaring and Agricultural, but they can only research Scaffolding and not Epic works. On the Anno Domini website, the primary trait is the one listed first under each civ. Each trait is a primary trait for a maximum of four civs.
Horseback Riding is a flavour tech also. The other options are Camel Riding and Elephant Riding - all leading to units of the same Att, Def, Movement values, but flavoured according to the civ.
Viticulture is for Mediterranean civs only. The other trade options - all of which lead to a luxury becoming available (such as wine with viticulture) and a small wonder dependant on the tech. The options are:
African civs: Salt mining - allows Salt Trade small wonder, which gives +1 trade to all squares already producing trade but must have access to salt.
Asian civs: Silk trading - allows Silk Trader, which requires access to silks. This small wonder gives +50% luxury output.
European civs: Tin mining - allows Tin Mine, which needs access to tin and gives a +25% shield output increase.
Mediterranean civs: Viticulture, leading to Vineyard if wine is accessible. The small wonder provides +2 happy citizens.
Middle-Eastern civs: Weaving, which allows a Weaver's House providing there is access to cloth. A +50% boost to the tax output is given with this small wonder.
I've done these as small wonders because I don't want them to be restricted to having the resource within the city limits but equally feel that one of these buildings is sufficient for each civ.