A recent comment under a question of mine prompted me to consider how 接続助詞 work syntactically, and to discover that different ones follow different 形 (Japanese Wikipedia has a nice list). However, no such classification seems to exist for 接続詞, which leads to the question: How do 接続詞 work syntactically?
Most commonly, they seem to exist at the start of clauses, such as
however, some also seem to be joining NPs
Since Japanese Wikipedia classifies these particular 接続詞 as 並立, it would be tempting to draw the analogy that these, similar to 並立助詞, connect NPs while others begin/connect clauses, but this is probably a simplification.
Thus: What are the types of 接続詞, and how can they be used syntactically?