What is the standard mnemonic phrase for planets (widely accepted)?

There is no widely accepted phrase that we could call a "standard". The first English-language mnemonics for the nine celestial bodies which were accepted as planets came up in the 1950s, the most used being probably "Men Very Easily Make Jugs Serve Useful Needs, Perhaps". Other common ones included:

"My Very Educated Mother Just Served Us Nine Potatoes"
or
"My Very Easy Method Just Shows Us Nine Planets"

After Pluto was declared a dwarf planet in 2006 there was a need for a new mnemonic phrase. Phyllis Lugger, professor of astronomy at Indiana University, suggested the following modification to the "potato mnemonic": "My Very Educated Mother Just Served Us Nachos".

Kyle Sullivan made a suggestion that was published in the January 2007 issue of the "Astronomy" magazine: "My Violent Evil Monster Just Scared Us Nuts"

Other suggestions came up making fun of the controversial decision of demoting Pluto:

"Many Very Educated Men Justify Stealing Unique Ninth"
"Many Very Educated Men Just Screwed Up Nature"
"My very easy memory jingle seems useless now"

Note that the three outermost planets are easy to remember as their initials are SUN. To include the others:
My Very Easy Memory Jog...SUN!