You can hide control from SharePoint ribbon bar using below CSS.
You can create new CSS file as per your requirement and then refence that CSS into master page.
Font Block
Entire font section:
#Ribbon\.EditingTools\.CPEditTab\.Font
Font face and size:
#Ribbon\.EditingTools\.CPEditTab\.Font-Large-0-0
Font face:
#Ribbon\.EditingTools\.CPEditTab\.Font\.Fonts-Medium
Font size:
#Ribbon\.EditingTools\.CPEditTab\.Font\.FontSize-Medium
Font formatting (all):
#Ribbon\.EditingTools\.CPEditTab\.Font-Large-0-1
Font formatting:
#Ribbon\.EditingTools\.CPEditTab\.Font-Large-0-1-0
Font formatting (Highlight and font color):
#Ribbon\.EditingTools\.CPEditTab\.Font-Large-0-1-1
Font formatting (Clear formatting):
#Ribbon\.EditingTools\.CPEditTab\.Font-Large-0-1-2
Bold:
#Ribbon\.EditingTools\.CPEditTab\.Font\.Bold-Small
Italic:
#Ribbon\.EditingTools\.CPEditTab\.Font\.Italics-Small
Underline:
#Ribbon\.EditingTools\.CPEditTab\.Font\.Underline-Small
Strikethrough:
#Ribbon\.EditingTools\.CPEditTab\.Font\.Strikethrough-Small
Subscript:
#Ribbon\.EditingTools\.CPEditTab\.Font\.Subscript-Small
Superscript:
#Ribbon\.EditingTools\.CPEditTab\.Font\.Superscript-Small
Highlight:
#Ribbon\.EditingTools\.CPEditTab\.Font\.FontBackgroundColor-Small
Font color:
#Ribbon\.EditingTools\.CPEditTab\.Font\.FontColor-Small
Paragraph Block
Entire paragraph section:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph
Paragraph formatting (Bullets, numbering, outdent/indent, paragraph direction):
#Ribbon\.EditingTools\.CPEditTab\.Paragraph-Large-0-0
Paragraph formatting (Alignment options):
#Ribbon\.EditingTools\.CPEditTab\.Paragraph-Large-0-1
Bullets and numbering:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph-Large-0-0-0
Bullets:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.Bullets-Small
Numbering:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.Numbering-Small
Outdent and indent:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph-Large-0-0-1
Outdent:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.Outdent-Small
Indent:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.Indent-Small
Paragraph direction (both):
#Ribbon\.EditingTools\.CPEditTab\.Paragraph-Large-0-0-2
Left to right:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.LTR-Small
Right to left:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.RTL-Small
Align left:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.AlignLeft-Small
Align center:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.AlignCenter-Small
Align right:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.AlignRight-Small
Justified:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.AlignJustify-Small
Style Block
Entire style section:
#Ribbon\.EditingTools\.CPEditTab\.Styles
Paragraph:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.RibbonStyle0-Large,
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.ElementWithStyle\.Menu\.Styles\.Gallery tr:first-child > td:first-child
Heading 1:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.RibbonStyle1-Large,
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.ElementWithStyle\.Menu\.Styles\.Gallery tr:first-child > td:nth-child(2)
Heading 2:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.RibbonStyle2-Large,
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.ElementWithStyle\.Menu\.Styles\.Gallery tr:first-child > td:nth-child(3)
Heading 3:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.RibbonStyle3-Large,
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.ElementWithStyle\.Menu\.Styles\.Gallery tr:first-child > td:nth-child(4)
Heading 4:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.RibbonStyle4-Large,
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.ElementWithStyle\.Menu\.Styles\.Gallery tr:first-child > td:nth-child(5)
Heading Alternate (All):
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.ElementWithStyle\.Menu\.Styles\.Gallery tr + tr
Heading 1 Alternate:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.ElementWithStyle\.Menu\.Styles\.Gallery tr + tr td:first-child
Heading 2 Alternate:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.ElementWithStyle\.Menu\.Styles\.Gallery tr + tr td:nth-child(2)
Heading 3 Alternate:
#Ribbon\.EditingTools\.CPEditTab\.Paragraph\.ElementWithStyle\.Menu\.Styles\.Gallery tr + tr td:nth-child(3)
Heading 4 Alternate: #Ribbon\.EditingTools\.CPEditTab\.Paragraph\.ElementWithStyle\.Menu\.Styles\.Gallery tr + tr td:nth-child(4)
Text Styles (All):
#Ribbon\.EditingTools\.CPEditTab\.Styles\.Styles\.Menu\.Styles
Text Styles 1st Row:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.Styles\.Menu\.Styles tr:first-child
Normal:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.Styles\.Menu\.Styles tr:first-child td:first-child
Quote:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.Styles\.Menu\.Styles tr:first-child td:nth-child(2)
Intense Quote:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.Styles\.Menu\.Styles tr:first-child td:nth-child(3)
Emphasis:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.Styles\.Menu\.Styles tr:first-child td:nth-child(4)
Intense Emphasis:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.Styles\.Menu\.Styles tr:first-child td:nth-child(5)
Text Styles 2nd Row :
#Ribbon\.EditingTools\.CPEditTab\.Styles\.Styles\.Menu\.Styles tr:nth-child(2)
Reference:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.Styles\.Menu\.Styles tr:nth-child(2) td:first-child
Intense Reference:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.Styles\.Menu\.Styles tr:nth-child(2) td:nth-child(2)
Accent 1:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.Styles\.Menu\.Styles tr:nth-child(2) td:nth-child(3)
Accent 2:
#Ribbon\.EditingTools\.CPEditTab\.Styles\.Styles\.Menu\.Styles tr:nth-child(2) td:nth-child(4)