I take it to have been an old Catholic cross; at least, I know not what else it is.
I know not what else to advize yow of for present, but, yf any thinge com to my remembrance heareafter, yow shall understand thereof per first.
I know not what else to write, but that my greatest sorrow is I lye in a place which hitherto hath byn chargable and not benefitiall to your Wors.
I know not what else to write, but leave yow to the protection of thallmightie, resting Your loving frend, RIC.
The above list will hopefully provide you with a few useful examples demonstrating the appropriate usage of "know not what else" in a variety of sentences. We hope that you will now be able to make sentences using this group of words.