ヶ

ヶ U+30F6, ヶ KATAKANA LETTER SMALL KE ← ヵ [U+30F5] Katakana ヷ → [U+30F7]

English Wikipedia has an article on:

Small ke

Wikipedia

An abbreviation for the kanji 箇 (ka), the counter for months, places or provisions.

Note that ヶ is a graphical abbreviation of the top of the character (𥫗, 竹), and is pronounced カ ka (or ガ ga), not as ケ ke. Compare simplified Chinese character 个.

ヶ or か • (ka) 

1. 箇: Counter for months, places or provisions of Classical Chinese origin.

   三(さん)ヶ(か)月(げつ) ― sanka getsu ― three months (in duration)

   三(さん)ヶ(か)国(こく) ― sanka koku ― three countries

• か
• カ
• ヵ
• 箇

ヶ or こ • (ko) 

1. 個: General counter for inanimates.

   ３(さん)ヶ(こ) ― sanko ― three objects

• 個

ヶ or が • (ga) 

1. An alternative spelling of an obsolete possessive marker が (ga). Found only in place names.

   藤(ふじ)ヶ(が)丘(おか) ― Fujigaoka ― a place name, literally "Hill of Wisteria"

• が
• ケ

• (Japanese ligatures and scribal abbreviations) 〆(しめ) (shime), 𪜈(とも) (tomo), ゟ (yori), ヿ (koto), 𬼀(して) (shite), 〼(ます) (masu), ヶ (“graphical abbreviation for 箇”), 々 (“iteration mark”), ゝ (“iteration mark for hiragana”), ヽ (“iteration mark for katakana”) 〱 (“iteration mark for multiple kana”),