What are DF card TF card respectively?

Also known as T-Flash card, full name: TransFLash, by Motorola and SANDISK*** with research and development, launched in 2004. It is a kind of ultra-small card (11*15*1MM), about 1/4 of SD card, can be considered the smallest memory card.TF card can be used as SD card after SD card converter. The adapter can be used in devices that use SD as a storage medium.TransFlash is mainly developed for camera phones to capture large images and to be able to download larger video clips.TransFlash cards can be used to store personal data such as digital photos, MP3s, games, and applications for cell phones and personal data, and have a built-in copyright protection and management system to allow downloads of music, images, and video clips to be stored on the card. It also has a built-in copyright protection system to protect downloaded music, videos and games, and future versions of TransFlash will include encryption to protect personal data, financial records and healthcare documents. The compact size of TransFlash allows manufacturers to adopt this design without worrying about the size of the phone, and another flexible application is that it can be replaced by the supplier at any time prior to delivery to meet the different needs of the customer, an advantage not available with embedded flash memory.

This is the first time I've heard of DF cards. I don't know what it is

The DF card is the first I've heard of.