A few quick thoughts on searching for names in online databases.
Keep a list of all spelling variants. You will not remember all of them all the time. Spelling variants usually result from pronunciation issues and transcription issues. For those with surnames that are not English the name may also have been anglicized, truncated, or otherwise altered.
These are not Soundex equivalent—a search for Buller performed with the soundex option turned on will not catch any of the other names. A wildcard search for Bu* will catch them all, but some sites do not allow wildcard operators to be used with only two characters.
The Trautvetter variants are all Soundex equivalent except for Trantvetter.
Determining the soundex code for a specific name is as easy as using an online site. There are several sites that will calculate the corresponding Soundex code for a surname, including:
If variants differ by one letter—such as Kile or Kyle, then a fixed length wildcard operator is the best approach. In this case k_le would be the desired search term. That will work as long as the site allows wildcard operators to be used after just one letter.
K*le will result in too many hits—Kastle, Kestle, Kurrle, etc. in addition to Kyle and Kile.
Be aware of diminutives, nicknames, middle names and anglicizations of first names.